WPF databinding to interface and not actual object - casting possible?

Say I have an interface like this:  public interface ISomeInterface { ... }   I also have a couple of classes implementing this interface;  public class SomeClass : ISomeInterface { ... }   Now I have a WPF ListBox listing items of ISomeInterface, using a custom DataTemplate.  The databinding engine will apparently not (that I have been able to figure out) allow me to bind to interface properties - it sees that the object is a SomeClass object, and data only shows up if SomeClass should happen to have the bound property available as a non-interface property.   How can I tell the DataTemplate to act as if every object is an ISomeInterface, and not a SomeClass etc.?  Thanks!


So I changed my name on my profile but when I go to it in the leaderboards, it still has my old name instead of my new one. Does anyone know how to fix this? Thanks!


In Windows Forms, I'd just override WndProc, and start handling messages as they came in.  Can someone show me an example of how to achieve the same thing in WPF?


In a Django form, how do I make a field readonly (or disabled) so that it cannot be edited?

In a Django form, how do I make a field read-only (or disabled)?  When the form is being used to create a new entry, all fields should be enabled - but when the record is in update mode some fields need to be read-only.  For example, when creating a new Item model, all fields must be editable, but while updating the record, is there a way to disable the sku field so that it is visible, but cannot be edited?  class Item(models.Model):     sku = models.CharField(max_length=50)     description = models.CharField(max_length=200)     added_by = models.ForeignKey(User)   class ItemForm(ModelForm):     class Meta:         model = Item         exclude = ('added_by')  def new_item_view(request):     if request.method == 'POST':         form = ItemForm(request.POST)         # Validate and save     else:             form = ItemForm()     # Render the view   Can class ItemForm be reused? What changes would be required in the ItemForm or Item model class? Would I need to write another class, "ItemUpdateForm", for updating the item?  def update_item_view(request):     if request.method == 'POST':         form = ItemUpdateForm(request.POST)         # Validate and save     else:         form = ItemUpdateForm()


If $g\circ f$ is injective and $f$ is surjective then $g$ is injective

Let $f:A\rightarrow B$ and $g:B\rightarrow C$ be functions, prove that if $g\circ f$ is injective and $f$ is surjective then $g$ is injective.  I need advise or correction if something is incorrect with my proof. Thank you beforehand.  We must show that $g$ is injective, i.e for $x,y\in B, g(x)=g(y)\implies x=y$  Let $x,y\in B$ such that $g(x)=g(y)$. Because $f$ is surjective there exists $a,b \in A$ such that $f(a)=x$ and $f(b)=y$  $\implies g(f(a))=g(f(b))$  $\implies g\circ f(a)=g\circ f(b)$  $\implies a=b$ (by injectivity of $g\circ f$)  $\implies f(a)=f(b)$  $\implies x=y$  Would appreciate any correction in proof writing also!


I am using Ubuntu 14.10 64bit and the latest version of VLC media player, when I play a video (MP4, MKV AVI etc... it doesn't matter) at the bottom of the screen there is a green line It isn't an issue with my OS, YouTube, and the default media player work fine. Has anyone else had this issue? and if so is there a fix or is it just a software bug?


Cannot get specific WMS to display in Leaflet or OpenLayers 3

I am trying to create a map in both Leaflet and OpenLayers 3 which displays the  layer EMAP8 from the WMS http://wms.nlsc.gov.tw/wms. I can't get it to work. I can open the layer in QGIS, but when I try to use it in Leaflet like this:  var overlay_taiwanemapen0 = L.tileLayer.wms('http://wms.nlsc.gov.tw/wms', {     layers: 'EMAP8',     format: 'image/png',     transparent: true,     continuousWorld : true, });   or in OpenLayers 3 like this:  var lyr_taiwanemapen = new ol.layer.Tile({     source: new ol.source.TileWMS(({         url: "http://wms.nlsc.gov.tw/wms",         params: {"LAYERS": "EMAP8", "TILED": "true"},     })),     title: "taiwane-map(en)", });   I get nothing displayed. I can see layers being requested, and data being transferred, but nothing on the map.  What am I doing wrong?


Missing file in / taking up all of the root space

I was copying a large VM disk file to a separate larger separate disk array to work on it and during a benchmark I did previously before I started the copy job I didn't realize that the benchmark had unmounted the array. So the file was partially copied to somewhere within the / filesystem and I cannot find it anywhere. I've looked with some commands like find -type f -exec du -Sh {} + | sort -rh | head -n 5 to the find the largest files. Any suggestions? Below are the file system outputs.  df -h Filesystem               Size  Used Avail Use% Mounted on /dev/mapper/centos-root   50G   50G  122M 100% / devtmpfs                  16G     0   16G   0% /dev tmpfs                     16G     0   16G   0% /dev/shm tmpfs                     16G   11M   16G   1% /run tmpfs                     16G     0   16G   0% /sys/fs/cgroup /dev/sda2               1014M  216M  799M  22% /boot /dev/sda1                200M   12M  189M   6% /boot/efi /dev/mapper/centos-home  864G  301G  563G  35% /home tmpfs                    3.1G   32K  3.1G   1% /run/user/1000 /dev/sdb1                1.9T  132G  1.7T   8% /disk1   du -sh * 0       bin 194M    boot 0       dev 46G     disk1 41M     etc 301G    home 0       lib 0       lib64 0       media 0       mnt 720K    opt du: cannot access ‘proc/39152/task/39152/fd/3’: No such file or directory du: cannot access ‘proc/39152/task/39152/fdinfo/3’: No such file ordirectory du: cannot access ‘proc/39152/fd/3’: No such file or directory du: cannot access ‘proc/39152/fdinfo/3’: No such file or directory 0       proc 4.9M    root du: cannot access ‘run/user/1000/gvfs’: Permission denied 11M     run 0       sbin 0       srv 0       sys 20M     tmp 3.5G    usr 673M    var


Saving active view into ArcGIS Pro project using ArcPy?

I have a desirable requirement to be able to set the active view (Layout, Map, Basemap, etc) in an ArcGIS Pro project using ArcPy.  However the  does not seem to provide a method to do this.  I would like to be able to make sure that a particular Layout in my ArcGIS Pro project is the view that a copy of my project (made using the saveACopy method) opens to when I give it to someone.  Is it possible to do this by any other means from ArcPy?  If I were using ArcPy with ArcMap the equivalent would be accessible in the activeView property of the MapDocument class.


Add a new `is_anon` attribute to Stack Exchange Questions to Implement Deletes which Aren't Really Deletes

A lot of people learning about computer programing for the first time write questions which they later become embarrassed about. In some cases the questions are legitimate, but the original poster (OP) will delete the question after a few months. I guess that the OP does not want to seem naïve, or something; I don't know. In some cases, when the question is deleted, a lot of well-written answers are deleted with along with the question. A few novice programmers next year will probably ask the same question. They might as well read the answer which have already been written. There is no need to delete the question out of embarrassment. I was wondering if a new attribute (or member-variable) could be added to question objects This would be known as a new "column" or "field" in SQL The new attribute could be a boolean, named something like is_anon When loading a stack overflow page, an can replace the user-name of the asker.  display_name = question.author.user_name if (q.is_anon) {     display_name = "Anonymous" }  I am hoping that when a user attempts to delete their own question, that the question will not really deleted. Instead, the is_anon attribute is set to True. If a moderator deletes the question, then the question should be truly deleted, not merely marked as anonymous. If a question's is_anon flag is set to true, then all hyperlinks targeting the OP's profile page will be replaced with the flavor text, and no link.


Is there any software that allows to draw block diagrams  like this:   or like this:


Can I get notification when event occur?

SQL Servers has Traces and XEvents. These are used to capture and analyze what is going on with our SQL Server Instances. Events are stored in the stack for later analysis. For example,  If I decide to monitor any dead lock in the database, I just query the trace file to see the history of deadlock for a period of time. Here is my question:  While events occur, in our example deadlock event, is there a way to get an email notification using msdb.dbo.xp_send_dbmail?


How to recover data from a damaged external drive?

Is it possible to recover data from a damaged external drive? My external drive was not recognized by my computers and after a computer engineer examined it, I was told the drive is damaged.   He claimed to have been able to view some of the files on the drive, but that they are damaged. How do I recover my files from this drive?


Let $$x=0.99999\ldots.$$  Clearly $x$ is a rational number.     I want to find $a,b$ such that    $$x=\frac{a}{b}.$$   Clearly $10x-x=9$ and thus $x=1$. So  $$1=0.99999\ldots$$  Where is my mistake?


Why do shell globs omit dot files by default?

1)   echo *  Only displays file names having [a-z, A-Z] but does not display files starting with .  For example .bashrc is not covered with shell glob *  2)  echo .* gives the expected output.    In first case, why does the shell glob does not include file names with dot?


Real solution of $(\cos x -\sin x)\cdot \bigg(2\tan x+\frac{1}{\cos x}\bigg)+2=0.$

Real solution of equation $$(\cos x -\sin x)\cdot \bigg(2\tan x+\frac{1}{\cos x}\bigg)+2=0.$$   Try: Using Half angle formula   $\displaystyle \cos x=\frac{1-\tan^2x/2}{1+\tan^2 x/2}$ and $\displaystyle \sin x=\frac{2\tan^2 x/2}{1+\tan^2 x/2}$  Substuting These values in equation  we have an polynomial equation in terms of $t=\tan x/2$  So our equation $$3t^{4}+6t^{3}+8t^{2}-2t-3=0$$ Could Some Help me how to Factorise it.  OR is there is any easiest way How to solve it, Thanks


I have been updating an old (from 1999) Python script to Python 3. Occasionally I have found . It is typically used in something like:  some_var = regex.compile(pattern, regex.casefold)   How would I go about changing this so it works in the latest Python 3?


When archiving Gmail email free up more space in Google Drive

When Archiving my email using Gmail does that help increase my storage in Google drive?  I have a Gmail account and I use Google Drive. I don't have a lot of pictures but I have used 11GB of my space.  At this rate I either have to buy more space or Delete my emails.  But if I archive them and they get stored somewhere else and free up my Google Drive that would be great.


What happens when writing to a device driver?  For example:   echo "some text" > /proc/device_driver   I'm guessing that echo has a write-call that somehow invokes the write-function in the driver.  What are the "steps" from the echo-function to the drivers write function?


This is probably a dupe, but I can't find the answer in the first few pages on google: how can I link to a tag in another tag snippet? [tag:<something>] doesn't seem to work.


Should I apply for a tourist visa as a US citizen traveling to the Schengen area this summer?

I have planned travel to Iceland, Germany and Spain this summer, from July 1st to July 21st. I see that EU Commission is now considering visa requirements for US citizens and may come to a decision by mid June.    How do I apply for a visa when there is no current requirement?


Teenagers taken from their worlds; attracted to colored gems which give them special powers

Long ago (15 years?), I partially read a novel which I really liked. I don't remember the title or full plot of it. I would be grateful if some one can identify it from the limited plot below:  Three (or four) teenagers are taken from their worlds (or different places on earth) to a strange world full of trolls, gems, powers etc. Each one gets attracted a particular colored gem which gives them a particular power. They keep going forward battling all obstacles to achieve some vague objective.


Increasing post view count automatically

I am testing a ranking system for posts, and I'd like help with the below:  Upon publishing a new post, I'd like the post view count to immediately have a random number between 829 and 1013 added to it.  Could you please tell me how I can do that? If you offer any code, kindly let me know exactly where to put it.  Thank you.


Undefined reference to function template in class template C++

I am trying to create a template class library in C++. The include file as follows foo.h #pragma once #include <iostream>  template<class T> class Foo {     Foo{}     ~Foo{}      template<typename B>      void bar1(B var);      void bar2(); }  Class functions are implemented in this file, foo.hpp #ifndef _FOO_H_ #define _FOO_H_  #include "foo.h"  template<class T> template<typename B>  void Foo<T>::bar1(B var) {     // code }  template<class T> void Foo<T>::bar2() {     // code }  #define  INSTANTIATE(T) template class foo<T> #endif  To link the template class foo.cpp #include "foo.hpp"  INSTANTIATE(int)  and in the CMakeLists.txt I have added the add_library(foo foo.cpp) and installed the library with all the dependency and it is building fine. Now in the implementation implementation.cpp #include "foo.h"  int main(int argc, char** argv) {     Foo<int> foo;     foo.bar2();     return 0; }  This executable file is building fine with no error. However, alternatively when I use the other function as follows, implementation.cpp #include "foo.h"  int main(int argc, char** argv) {     Foo<int> foo;     std::string a = "hello";     foo.bar2(a.c_str());      return 0; }  I am getting the undefined reference to bar2 function error during the build. Can someone please help with this problem. Thank you in advance. Best Regards, Vishnu


Is there a design pattern for dropdown lists in iOS?

I've searched quite a bit for this but surprisingly could not find any comprehensive answer. XCode doesn't provide any simple way to add dropdown lists to iOS interfaces. Stackoverflow just showed workarounds and long code just to get a simple dropdown list. This leads me to believe that the design pattern is to not really use dropdown lists! Is this true? And if so, what is the recommended alternative?


Is this circuit for Piezo Transducer and corresponding resistor values correct?

I want to drive this piezo transducer () at 3V and 4kHz with STM32F0 microcontroller. This is a follow-up to my previous question (). Since then, I've made some progress and come up with this circuit:         – Schematic created using   R1 is to limit the amount of current the microcontroller pin draws and R2 is to discharge the speaker when there is no output to the speaker (since it acts like a capacitor). The MCU can draw a max of 25mA of current, but the speaker only uses a max of 5mA when driven at 3V and 4kHz. So I will limit the current draw from the MCU to 10mA. This gives i_c a value of 10mA and R1 a value of \$330\Omega\$.  (R1 = \$\frac{3.3V}{10mA}\$). Since the speaker draws a max of 5mA, i_s = 5mA and i_b = 5mA. The schematic with the values plugged in is:          To determine R2, I know I want 3V to be applied to the speaker, so the voltage drop over R2 will be 3V. Using Ohm's Law, \$R2 = \frac{3V}{5mA} = 600\Omega\$.  My two main questions are:   Is this circuit fundamentally correct to drive the transducer? Do the values for resistors R1 and R2 make sense or am I overlooking something?


Convergence or not of infinite series: $\sum^{\infty}_{n=1}\frac{n}{1+n^2}$

How can we prove that the series $\displaystyle \sum^{\infty}_{n=1}\frac{n}{1+n^2}$ is convergent or divergent?  Solution I try:  $$\lim_{m\rightarrow \infty}\sum^{m}_{n=1}\frac{n}{1+n^2}<\lim_{m\rightarrow \infty}\sum^{m}_{n=1}\frac{n}{n^2}$$  Did not know how I can solve that problem from that point.


HP Proliant Gen8 boot failure after bios upgrade and processor upgrade

We have a HP Proliant DL360P with one Intel Xeon e5-2650, and we was in need to use two Xeon e5-2670 V2, this server by default this G8 did not recognizes the v2 processor, so we found  so we did the BIOS Firmware update to most recently (2014) and after we did the processor self-upgrade procedure as described on the link.  Changed the processor and it worked, and after a power-off / power-on it did not booted, in the SID panel it said that the processor was the fault, so we changed back the processor to the e5-2650, and it keept saying that the processor was the fault.  We removed the batery to clear the BIOS and after it botted but appeared a very mess strange characters in the display.  I'm now downloading the Firmware maintenance v10.1 from FTP of HP to make the procedure  but I want to check with you if with your knowledged if you now something about it


How many permutations of {1,2,…,9} are there such that 1 does not immediately precede 2, 2 does not immediately precede 3, and so forth up to 8 not immediately preceding 9? One obvious example of such a permutation might be 987654321, but there are many others, such as 132465879 or 351724698.


I have just installed Ubuntu 18.04 on my Asus UX490 and now I cannot change the volume but I can mute/unmute.  I can move the volume bar right/left but volume does not change. However, when I move it to left most side or just click the sound icon, computer mutes/unmutes correctly.  Also when I try to change the volume with fn+f11/f12 I see the volume level thingy changing in the middle of the screen but sound does not change as well. However, again, I can mute/unmute with fn+f10.  Similar things happen when I try from Setting > Sound. Under this menu in the "Choose a device for sound output:" list I only see "Speakers - Built-in Audio".  Another thing, if I change the sound in a player (let's say youtube) sound changes.  I tried these two but they did not help.       PS: Just to make it clear, this is the first time I installed any Ubuntu version on this laptop. I mean, I do not say "it was working and got broken after I installed 18.04"


Old title - "change resolution to 1280x1024 using xrandr gives: X Error of failed request: BadValue (integer parameter out of range for operation)"  I have installed a fresh Ubuntu 17.10 and have a monitor with 5:4 resolution. settings has no resolution higher than 1024x768. But I need the resolution 1280x1024 (5:4).  I use the default motherboard graphics card:  # lspci|grep VGA 00:02.0 VGA compatible controller: Intel Corporation 4 Series Chipset Integrated Graphics Controller (rev 03)   Also xrandr gives the following:  $ xrandr Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192 XWAYLAND0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm    1024x768      59.92*+   I tried to add the 1280x1024 resolution using xrandr. so first created the resolution information using gtf:  $ gtf 1280 1024 60    # 1280x1024 @ 60.00 Hz (GTF) hsync: 63.60 kHz; pclk: 108.88 MHz   Modeline "1280x1024_60.00"  108.88  1280 1360 1496 1712  1024 1025 1028 1060  -HSync +Vsync   Then added to resolutions:  xrandr --newmode "1280x1024_60.00"  108.88  1280 1360 1496 1712  1024 1025 1028 1060  -HSync +Vsync   then again did the command: xrandr --addmode XWAYLAND0 1280x1024_60.00  Then nothing changed. When I tried to change it using xrandr --output XWAYLAND0 --mode 1280x1024_60.00 --rate 60 But an error occurred:  $ xrandr --output XWAYLAND0 --mode 1280x1024  --rate 60 X Error of failed request:  BadValue (integer parameter out of range for operation)   Major opcode of failed request:  140 (RANDR)   Minor opcode of failed request:  7 (RRSetScreenSize)   Value in failed request:  0x0   Serial number of failed request:  21   Current serial number in output stream:  22   I don't know what did I do wrong. Or how to change resolution to the correct one: 1280x1024


How to figure out someone's seed in Minecraft?

I don't want to have to deal with terrain when I am rebuilding someone's world on PC Minecraft. They started their world before 1.8 and so I cannot look at F3 to find the seed. Does anyone have an answer?


I've never been quite able to figure out how groups work in Blender (at least not since 2.5/6x). Is it possible to group several objects and then manipulate them (scale, rotate, translate) as one?


Where is this text tutor? I keep finding references to it but only get an empty document when I run it.


Is it possbile to prevent a directory from being listed in Windows?

I'm using Windows Home Server 2011 and connecting to it with various Windows 7 version clients.  Suppose I have a shared directory (or server folder) mydir on my WHS box which contains a subdirectory private.  When a given client lists the contents of mydir, is it possible to instruct WHS to display private only if the given user is authorized?  It's easy enough to prevent access to private but I don't even want it listed.  Note that marking the directory as hidden is not at all what I want to do since that would also force an authorized user to change the viewing state of hidden directoies and files and could be easily undermined by anyone that can list the contents of mydir.


"It is to be discussed", what is the infinitive doing in this sentence?

It is to be discussed.   Is be + infinitive forming the future tense here?      You are to be dressed and ready by 8:00.   I was thinking it's almost commanding (or speaking of a command) but this doesn't seem to be the case, as sentences like this are commanding without this structure:     You will be dressed and ready by 8:00.   or      You are going to be dressed and ready by 8:00.   And there's sentences like this that don't imply commandment in any way:     I am to go home tomorrow!   or     I am to be home tomorrow!   (Slightly different meaning, same general sentiment)  So what's going on with the be + infinitive structure?


Just thinking of/about the smell makes me want to throw up!

Someone was talking about cats and I said I'm not a pet person mainly because of their poops. Then I said: "Just thinking about the smell makes me want to throw up." Even though I said 'about' I feel like I should have said 'of' since thinking about means actively thinking about something and thinking of means you are least aware about it/an idea comes to your mind. Since I don't actively think about cat poops. Should I have said 'of?'


The derivative of the area $A(r) = \pi r^2$ of a circle with radius $r$ gives the circumfence $\frac{dA(r)}{dr} = 2\pi r$.  Similarly, the derivative of the volume $V(r) = \frac{4}{3}\pi r^3$ of the sphere (ball) with radius $r$ gives the surface area $\frac{dV(r)}{dr} = 4\pi r^2$.  This is not true say for the square or the square cuboid.  Just a coincidence. Stupid question I know.


a few days ago I had a asked a question regarding longer lasting batteries for a walking robot built with a Tamiya gearbox. Since the AA batteries were being depleted too fast, it was suggested that I use D cells. I would like to know would using C or D batteries instead of AA spoil the motor? Even though the voltage is same, the current is different.  Thanks.


(JS) why 2 date type variables share the same content?

Can you help me to understand why d1 has different value in each alert() ? Thanks.  <script> d1 = new Date("01/01/2015"); d2 = d1; alert(d1); d2.setDate(d2.getDate()+10); alert(d1); </script>


Is it always true that  $(A_1 \cup A_2) \times (B_1 \cup B_2)=(A_1\times B_1) \cup (A_2 \times B_2)$?  I don't believe this is true. I have tried to draw pictures to help me get on the right path, but I think that the union makes this untrue. for example, if $a \in A_1$ and $b \in B_2$, then $(a,b)$ would not be in $(A_1\times B_1) \cup (A_2 \times B_2)$. Is this a correct assumption?


How is the damage reduction calculated from armor/mr?

For example, if your champion has 200 magic resistance / armor and your enemy has some crazy AP/AD damage that can be dealt with one single spell/attack, say 800 damage at once...  Considering the enemy doesn't have any magic/armor penetration (not even MPen/APen runes), how much damage would your champion receive?


My mom bought some toys from a woman with a very sick son. They had yet to find out what was wrong with him. The toys have sat in an unheated detached garage for more than 2 months. Will they be safe for an infant to play with? Some are electronic, so it is hard to get them completely sanitized.


When a user account is deleted, what decides when to preserve and remove the votes of the user?

When a user account is removed (either by request or due to violating the network's terms of service), the users of the site lose or gain some reputation because their votes are also removed along with their account details.   From relevant ,     This message means that a user who voted for one of your posts had their account deleted (either by request or due to violating the network's terms of service). As a result, all of their votes were removed, and the reputation you gained or lost from them was undone. The resultant reputation change could be any amount; it could even be a reputation gain if enough of the removed votes were downvotes. All the reputation changes from a single user's deletion are rolled into a single event in the reputation page labelled "User was removed".   But I noticed that when a user account was deleted on one of the sites I participated, I didn't gain or lose any reputation. I know that he has upvoted my answers posts from his comments and messages in the chat rooms.  So, I came to know that votes are not removed in all the cases.  On what basis it is decided when to remove the votes and when to preserve? Does the criteria differ for deletion by the request of users?   Shog9 in an  to there are certain thresholds when the user is involved in voting fraud but my question is about accounts deleted by request also.


Is there a symbol in LaTeX for ⌘?  More info about it:


How to interpret this yum dependency error?

I'm trying to install XRDP and I'm hitting the following:  [root@box ~]# yum -y install xrdp Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile  * base: centos.serverspace.co.uk  * epel: mirrors.coreix.net  * extras: mirror.sov.uk.goscomb.net  * updates: mirror.sov.uk.goscomb.net Resolving Dependencies --> Running transaction check ---> Package xrdp.x86_64 1:0.9.10-1.el7 will be installed --> Processing Dependency: xrdp-selinux = 1:0.9.10-1.el7 for package: 1:xrdp-0.9.10-1.el7.x86_64 --> Processing Dependency: xorgxrdp for package: 1:xrdp-0.9.10-1.el7.x86_64 --> Running transaction check ---> Package xorgxrdp.x86_64 0:0.2.10-4.el7 will be installed --> Processing Dependency: xorg-x11-server-Xorg(x86-64) = 1.20.4 for package: xorgxrdp-0.2.10-4.el7.x86_64 ---> Package xrdp-selinux.x86_64 1:0.9.10-1.el7 will be installed --> Finished Dependency Resolution Error: Package: xorgxrdp-0.2.10-4.el7.x86_64 (epel)            Requires: xorg-x11-server-Xorg(x86-64) = 1.20.4            Installed: xorg-x11-server-Xorg-1.20.1-5.6.el7_6.x86_64 (@updates)                xorg-x11-server-Xorg(x86-64) = 1.20.1-5.6.el7_6            Available: xorg-x11-server-Xorg-1.20.1-3.el7.x86_64 (base)                xorg-x11-server-Xorg(x86-64) = 1.20.1-3.el7            Available: xorg-x11-server-Xorg-1.20.1-5.el7.x86_64 (updates)                xorg-x11-server-Xorg(x86-64) = 1.20.1-5.el7            Available: xorg-x11-server-Xorg-1.20.1-5.1.el7.x86_64 (updates)                xorg-x11-server-Xorg(x86-64) = 1.20.1-5.1.el7            Available: xorg-x11-server-Xorg-1.20.1-5.2.el7_6.x86_64 (updates)                xorg-x11-server-Xorg(x86-64) = 1.20.1-5.2.el7_6            Available: xorg-x11-server-Xorg-1.20.1-5.3.el7_6.x86_64 (updates)                xorg-x11-server-Xorg(x86-64) = 1.20.1-5.3.el7_6  You could try using --skip-broken to work around the problem  You could try running: rpm -Va --nofiles --nodigest   Now, I get that it's missing a dependency, however, it appears to be saying it requires xorg-x11-server-Xorg version 1.20.4.   It then continues to say version 1.20.1-5.6.el7_6 is installed.  From where I'm sitting, 4 is in the range 1-5 so I'm unclear what the issue is. They all seem to be for the right architecture.  Is 1-5 a version string in and of itself as opposed to a range, or -if not- what am I missing?  Solution: Thanks to , here's a workaround:     Having the same issue, I installed manually archived xorgxrdp   yum -y install https://archive.fedoraproject.org/pub/archive/epel/7/x86_64/Packages/x/xorgxrdp-0.2.9-1.el7.x86_64.rpm   then   yum -y install xrdp and it works


I am making a sphere with the radius of earth (6371000 meters). I have only limited zoom out and that makes it impossible to add something on the terrain. If I press F, it does not zoom out further than I could before. I tried to add a very large object like terrain and hitting F, but the zoom was still not sufficient.   I am using Unity 5.2.1


Invariance of a maximally entangled state under unitary operation $U \otimes U^\dagger$

Apparently the (d-dimensional) maximally entangled state, $|E \rangle = \sum_{i} |ii\rangle /\sqrt{d}$ is invariant under operations of the form $U \otimes U^\dagger$. I want to prove this result, which amounts to showing that  $$\left(\sum_i U | i \rangle \otimes V |i \rangle = \sum_i | ii \rangle \right)\Rightarrow (V = U^\dagger )$$  I have no idea how to even start. I suppose it's some simple linear algebra result, but I don't see it. A hint would be appreciated.


OK, this question may be induced by my highly commutative mind and the wee midnight hours.  Why do we bother with right R-modules vs left R-modules in view of the fact that given, say, a left R-module (M,+,$*$) (with scalar multiplication $*$) it is instantly a right R-module (M,+,$\circ$) with same addition and right multiplication $m\circ r =: r*m$ -- I believe the axioms for a right module check. In other words, in this way we have an isomorphism of the categories of right and left R-modules: RMod $\cong$ ModR  ???  Thus, whatever we say about one of these categories (or their objects and morphisms) is instantly true for the other? No? I may be wrong, but do people use a phrase "let us assume that M is an R-R bimodule" or something like that? Could they mean M is a left R-module and a right R-module with some secret scalar multiplication on the right, other than the one I defined above?   Now that @Qiaochu et al found an error in my thinking, pointing out that the categories of right and left R-modules may be quite different, let alone isomorphic, then why is it, that one waives one's hands often saying "This argument works exactly the same way for right R-modules as the one we just exhibited for the left R-modules." ? This in spite of the fact that the two categories may be totally different. Do we have any fair mechanisms enabling us to know when the proofs are left-right independent, or is it that we can say that only after we actually check the proofs one line at a time...?


Get the cartesian product of a series of lists?

How can I get the Cartesian product (every possible combination of values) from a group of lists?  Input:   somelists = [    [1, 2, 3],    ['a', 'b'],    [4, 5] ]   Desired output:  [(1, 'a', 4), (1, 'a', 5), (1, 'b', 4), (1, 'b', 5), (2, 'a', 4), (2, 'a', 5) ...]


Uniformly convergent implies equicontinuous

I'm trying to prove that if I have a sequence of continuously differentiable functions $f_n$ that converge uniformly on $[a,b]$, then $\{f_n\}$ is equicontinuous for all $x_0 \in [a, b]$. My idea is to use uniform convergence to deal with the "tail" and then use continuity to deal with the finitely many $f_n$'s left. But I'm having trouble writing it down.


Explicit bijection between $\Bbb R$ and permutations of $\Bbb N$

The set of permutations of the natural numbers has the cardinality of the continuum. I've got injections in both directions, no problem. The Schröder–Bernstein theorem tells us that this implies the existence of a bijection. I'm wondering if it's possible to construct one explicitly.  (In what follows, I'm using the convention that $0\not\in\Bbb N$. This obviously doesn't change anything, cardinality-wise.)    For $\Bbb R\to S_\Bbb N$, we note that every real number is the limit of some rearrangement of the alternating harmonic series. If $\alpha\in\Bbb R$, we start with positive terms: $1+\frac13+\frac15+\cdots$, until we obtain a partial sum greater than $\alpha$. We then add negative terms until our partial sum is less than $\alpha$, then we switch back to the positive terms, starting with the first unused one, etc.  In this way, we construct a series, and if we take the absolute values of the reciprocals of the terms of it, we have a permutation of $\Bbb N$. This mapping is not onto, because many permutations of the series converge to $\alpha$ - all we have to do is "overshoot" at some point, and then continue converging to $\alpha$ as usual. (More trivially, we only get permutations with $\sigma(1)=1$ using this particular construction.)    In the other direction, if we have a permutation $\sigma\in S_\Bbb N$, we can write the continued fraction $[\sigma(1);\sigma(2),\sigma(3),\ldots]$. This actually injects $S_\Bbb N$ into $\Bbb R\setminus\Bbb Q$, because non-terminating continued fractions represent irrational numbers. Thus, this mapping is not onto; it is not even onto the irrationals.For example, no permutation of $\Bbb N$ maps in this way to any quadratic irrational, or to $e$, or to any other irrational whose c.f. expansion has repeated terms.    So, those injections are fun and all, but finding an explicit bijection seems hard. Clearly, a bijection between $S_\Bbb N$ and any interval would suffice, because there are standard, elementary ways to construct bijections between $\Bbb R$ and any interval.  I have Googled in vain for a solution, and I don't believe this question is a duplicate. I will be happy for a hint or a full solution, or an explanation of why such an explicit construction is impossible.  Full disclosure: someone online claimed that this is "not hard", but refused to explain how, other than mentioning the Cauchy sequence construction of the reals. I don't see how that's useful, and I think he's mistaken or bluffing. I'm not too proud to admit I'm stumped. :/


I have simple code Scenario:  class Demo {    static void check(int z[])  {    z=null;  }   }  class arrNullCheck {   public static void main(String args[])  {     int arr[]={2,3,4,5};      Demo.check(arr);      for(int i=0;i<4;i++)      {        System.out.print(arr[i]);        }        } }   According to me this program should throw null pointer exception at runtime as z is equal to null,But output is as follows:  Output: 2 3 4 5   If i update method like:   static void check(int z[])  {    z[0]=9;  }    then it will update array with value 9 as expected. why doesn't null work here then ?


How to Format the Live USB I Made with Ubuntu

I created a Live USB with Ubuntu of another os. How can I completely delete that Live USB info if it only shows some kb's of memory and can't access the files of that Live USB?


Can anyone give me a hint to evaluate this integral?  $$\int_0^\infty \frac{dx}{1+x^4}$$  I know it will involve the gamma function, but how?


Log in loops again for a particular user

I was logging into my ubuntu machine till last night. Today I had an error unknown group ID error for the group I was in and also the UID. But I had no errors till the last night. I lost my sudo access too. I can ssh into my machine and account but when I log in to through GUI I get a blank screen and Then I added the group ID to /etc/group. I can't login after editing them. karthik.singaravelan is my username here. Here are the /etc/group and /etc/passwd files  root:x:0:karthik.singaravelan daemon:x:1: bin:x:2: sys:x:3: adm:x:4:aspire tty:x:5: disk:x:6: lp:x:7: mail:x:8: news:x:9: uucp:x:10: man:x:12: proxy:x:13: kmem:x:15: dialout:x:20: fax:x:21: voice:x:22: cdrom:x:24:aspire floppy:x:25: tape:x:26: sudo:x:27:aspire audio:x:29:pulse dip:x:30:aspire www-data:x:33: backup:x:34: operator:x:37: list:x:38: irc:x:39: src:x:40: gnats:x:41: shadow:x:42: utmp:x:43: video:x:44: sasl:x:45: plugdev:x:46:aspire staff:x:50: games:x:60: users:x:100: nogroup:x:65534: libuuid:x:101: crontab:x:102: syslog:x:103: fuse:x:104: messagebus:x:105: bluetooth:x:106: scanner:x:107: colord:x:108: lpadmin:x:109:aspire ssl-cert:x:110: lightdm:x:111: nopasswdlogin:x:112: netdev:x:113: whoopsie:x:114: mlocate:x:115: ssh:x:116: avahi-autoipd:x:117: avahi:x:118: pulse:x:119: pulse-access:x:120: utempter:x:121: rtkit:x:122: saned:x:123: aspire:x:1000: sambashare:x:124:aspire mysql:x:125: rabbitmq:x:126: mongodb:x:127:mongodb memcache:x:128: tomcat6:x:129: karthik.singaravelan:x:1001:   /etc/passwd   root:x:0:0:root:/root:/bin/bash daemon:x:1:1:daemon:/usr/sbin:/bin/sh bin:x:2:2:bin:/bin:/bin/sh sys:x:3:3:sys:/dev:/bin/sh sync:x:4:65534:sync:/bin:/bin/sync games:x:5:60:games:/usr/games:/bin/sh man:x:6:12:man:/var/cache/man:/bin/sh lp:x:7:7:lp:/var/spool/lpd:/bin/sh mail:x:8:8:mail:/var/mail:/bin/sh news:x:9:9:news:/var/spool/news:/bin/sh uucp:x:10:10:uucp:/var/spool/uucp:/bin/sh proxy:x:13:13:proxy:/bin:/bin/sh www-data:x:33:33:www-data:/var/www:/bin/sh backup:x:34:34:backup:/var/backups:/bin/sh list:x:38:38:Mailing List Manager:/var/list:/bin/sh irc:x:39:39:ircd:/var/run/ircd:/bin/sh gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh nobody:x:65534:65534:nobody:/nonexistent:/bin/sh libuuid:x:100:101::/var/lib/libuuid:/bin/sh syslog:x:101:103::/home/syslog:/bin/false messagebus:x:102:105::/var/run/dbus:/bin/false colord:x:103:108:colord colour management daemon,,,:/var/lib/colord:/bin/false lightdm:x:104:111:Light Display Manager:/var/lib/lightdm:/bin/false whoopsie:x:105:114::/nonexistent:/bin/false avahi-autoipd:x:106:117:Avahi autoip daemon,,,:/var/lib/avahi-autoipd:/bin/false avahi:x:107:118:Avahi mDNS daemon,,,:/var/run/avahi-daemon:/bin/false usbmux:x:108:46:usbmux daemon,,,:/home/usbmux:/bin/false kernoops:x:109:65534:Kernel Oops Tracking Daemon,,,:/:/bin/false pulse:x:110:119:PulseAudio daemon,,,:/var/run/pulse:/bin/false rtkit:x:111:122:RealtimeKit,,,:/proc:/bin/false speech-dispatcher:x:112:29:Speech Dispatcher,,,:/var/run/speech-dispatcher:/bin/sh hplip:x:113:7:HPLIP system user,,,:/var/run/hplip:/bin/false saned:x:114:123::/home/saned:/bin/false aspire:x:1000:1000:aspire,,,:/home/aspire:/bin/bash sshd:x:115:65534::/var/run/sshd:/usr/sbin/nologin mysql:x:116:125:MySQL Server,,,:/nonexistent:/bin/false rabbitmq:x:117:126:RabbitMQ messaging server,,,:/var/lib/rabbitmq:/bin/false mongodb:x:118:65534::/home/mongodb:/bin/false memcache:x:119:128:Memcached,,,:/nonexistent:/bin/false tomcat6:x:120:129::/usr/share/tomcat6:/bin/false karthik.singaravelan:x:1001:1001::/home/karthik.singaravelan:/bin/sh   output of id karthik.singaravelan  uid=1001(karthik.singaravelan) gid=1001(karthik.singaravelan) groups=1001(karthik.singaravelan),0(root),1352140539(power^users),1352554700(linux),1352139265(domain^users)   Is there any error with the config files that lets me not to log in? Other users can log in from my machine and I can log in from others machines. Whenever I press enter to login it goes black and returns to the screen. Kindly help me on this issue.


From the third week ( when does it actually begin)

This describes a certain natural process that takes 15 weeks  It describes what a certain component looks like at some point in time during a naturallly occurring process  What I don't get is if it means it appears this way starting in the third week or after ?  Here's the full sentence  "The malleus first appears as a cartilage model from the third week"  Thanks again for you support guys


Can't see PuTTY window on Windows Vista any longer

Recently I found that I could launch PuTTY but that no window was displayed. The Task bar has putty as a running application and I can right click on that to get the move and close option.  If I choose 'move', I get the outline of the PuTTY window to move but still no actual putty configuration window.   If I remote desktop to the same machine, I can launch PuTTY without any issues.


What is the displacement of an accelerated and relativistic object?

Displacement in an accelerated classical object is: $$s=ut+\frac {at^2}{2}$$ What is the displacement of an accelerated relativistic object?  In Newtonian mechanics there are two types of displacement.   Displacement of an object with velocity constant: $$s=ut$$ Displacement of an accelerated object with acceleration constant: $$s=ut+\frac {1}{2}at^2$$   This is not completely clear, but I think the second displacement should be something different in relativity. Is that true?  What is the result of this integral in relativity? $$s=\int (u+at)dt$$ classicaly $$s=\int (u+at)dt=\int udt +a\int tdt=ut+a\frac {t^2}{2}+x_0$$  What is the relativistic one?  more details: $$v=u+at$$ $$s\to displacement$$ $$a\to acceleration$$ $$u\to initial \,velocity$$ $$v\to final \,velocity$$


Been searching but still not sure what to do...  I have one computer with Windows7 and set up perfectly how we need it (programs, files, restrictions, etc...). I bought 4 more of the exact same computers for the office that I want set up exactly the same.  How can I create an image or bootable USB that encapsulates the one that is set up and install it on the new computers? Is sysprep the way to go?  Also, the new computers do not have anything installed on them. No OS, or anything at all.  Thanks in advance!


How can I mount a remote drive that I can only access via SSH agent forwarding?

I apologize if the question title is unclear.   To clarify, I have to SSH into server1 and then SSH from there into server2. Server2 is where the folder I need to mount is located. I've tried setting the tunnel up using Putty and PAC Manager, but I'm not sure if I'm doing it correctly.  My public key is already on both servers and I can authenticate just fine to both while using the -A flag to access server1.  I'm on Ubuntu 18.04. I don't know what kind of log/config I'd need to copypasta here, but I will provide them if requested.   I was told I could do this by someone who set it up correctly on a Mac with Secure Pipes and Fuse. I have Fuse on this installation, as well as SSHFS.  Any help is greatly appreciated!  EDIT TO REFUTE POSSIBLE DUPLICATE FLAG: The only way I see the 'duplicate' post being helpful is if I'm supposed to use the proxy command host as the sshfs host.


Utilities like host and dig let you see the IP address corresponding to the host name.  There is also the getent utility that can be used to query /etc/hosts or other NSS databases.  I am looking for a convenient standard utility (which is available in Debian, say) which resolves a host name regardless of where it is defined.  It should be more or less equivalent to  ping "$HOST" | head -1 | perl -lne '/\((.*?)\)/ && print $1'


Employee and employer 401k contribution limits

From my understanding, in 2020, the maximum an employee can contribute to their 401k is $19,500. The total contribution limit for an employee and employer combined in 2020 is $57,000. Now I understand that some companies have matching whether it's 25% or 50% or sometimes 100% but how do people reach that $57,000 limit? If I contribute the max to my 401k ($19,500), that means to reach the total contribution limit, the company must put in $57,000 - $19,500 = $37,500. Which means the company is almost contributing a 200% match? Is this correct? Do some companies actually match that much? The other thing I need clarified, is I read that the $19,500 is the max contribution that can be tax exempt. You are allowed to put after tax dollars in your 401k until the limit of $57,000 is reached. Is this true?


Why doesn't row data show up in SQL Developer?

I'm using Oracle database and I've created a test table "Table1" with a varchar column "column1". I ran the following loop to add some rows:  BEGIN     FOR i in 1..10 LOOP         INSERT INTO TABLE1 (COLUMN1)          VALUES (i);     END LOOP; END;   If I run 'select count(*) from table1' I get '10' as my result. However, in SQL Developer, nothing shows up. I can add rows manually and commit them to the database(these appear in SQL Developer), but I can't seem to view the ones created in sqlplus command line. Why is that?


How do I add SSL to a .net application that uses httplistener - it will *not* be running on IIS

Most recent edits in bold I am using the .net HttpListener class, but I won't be running this application on IIS and am not using ASP.net.  This  describes what code to actually use to implement SSL with asp.net and  describes how to set up the certificates (although I'm not sure if it works only for IIS or not).    The class documentation describes various types of authentication (basic, digest, Windows, etc.) --- none of them refer to SSL.  It does say that if .  Is this going to be a one line property setting and HttpListener figures out the rest?    In short, I need to know how to set up the certificates and how to modify the code to implement SSL.  Although it doesn't occur when I'm trying to access HTTPS, I did notice an error in my System Event log - the source is "Schannel" and the content of the message is:     A fatal error occurred when attempting   to access the SSL server credential   private key. The error code returned   from the cryptographic module is   0x80090016.   Edit: Steps taken so far   Created a working HTTPListener in C# that works for HTTP connections (e.g. "" Created a certificate using makecert.exe Added the certificate to be trusted using certmgr.exe Used Httpcfg.exe to listen for SSL connections on a test port (e.g. 8090) Added port 8080 to the HTTPListener via listener.Prefixes.Add("); tested an HTTP client connection, e.g. (") in a browser and receive correct return tested an HTTPS client connection, e.g. (") in a browser and receive "Data Transfer Interrupted" (in Firefox) debugging in visual studio shows that the listener callback that receives the requests never gets hit when the HTTPS connection starts - I don't see any place that I could set a breakpoint to catch anything else earlier. netstat shows that listening ports are open for both HTTPS and HTTP.  the HTTPS port does go to TIME_WAIT after a connection is attempted.  and  don't catch any of the traffic, I guess it doesn't get far enough in the process to show up in those HTTP analysis tools   Questions   What could the problem be?  Is there a piece of .Net code I am missing (meaning I have to do more in C# other than simply add a prefix to the listener that points to HTTPS, which is what i have done) Have a missed a configuration step somewhere?  What else might I do to analyze the problem? Is the error message in the System Event log a sign of the problem?  If so how would it be fixed?


Port Forwarding to a VMware Workstation Virtual Machine

I am running VMware Workstation 8 (build 471480). I want to setup a small content server, mainly for images and such for my website, on my desktop in a virtual server (just for the heck of it)... I now have everything installed on a VMWare virtual machine running Ubuntu Server and already have the web server running. I have tested it and it works fine within the network when accessing it from the host.  I now need to make it work on the public Internet and am planning on using noip.com, as i have done on many other occasions.  The problem is that my router is a Linksys E2500 and it only allows port forwarding to IPs within its subnet (192.168.2.**)  The host system connected to the router has an IP of 192.168.2.177. The VMware Workstation 8 virtual machine has a Network type of NAT and the IP for the server on it is 192.168.43.130.  I have already forwarded port 80 and 22 to 192.168.2.177, but how can i get my Windows 7 system to then forward that port to the server ip?


Derivation of inverse sine, what is wrong with this reasoning?

I'm trying to find the derivative of $\sin^{-1}(x)$. I know the steps that lead to $\frac{1}{\sqrt{1-x^2}}$, however I don't understand why the following reasoning leads to a wrong answer.  Because  $$\frac{d}{dx}f^{-1}(x) = \frac{1}{f'(f^{-1}(x))} $$  If we plug in for $f(x) = \sin(x)$, and because $\frac{d}{dx}\sin(x) = \cos(x)$ we get  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\sin^{-1}(x))} $$  Since $\sin(x) = \cos(x-\frac{\pi}{2})$, we can state that $\sin^{-1}(x) = \cos^{-1}(x-\frac{\pi}{2})$. (I suspect this is what is wrong)  Thus,  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{\cos(\cos^{-1}(x-\frac{\pi}{2}))}$$  Then, by the definition of inverse function, we have  $$\frac{d}{dx}\sin^{-1}(x) = \frac{1}{x - \frac{\pi}{2}}$$


Is it true that if $\gcd(a,b,c)=1$ then there exists $x,y\in\mathbb{Z}$ such that $\gcd(a+xc,b+yc)=1$?   I came upon this while trying to prove that the natural homomorphism $r_m:\operatorname{SL}_n(\mathbb{Z})\to\operatorname{SL}_n(\mathbb{Z}/m\mathbb{Z})$ is surjective. I was trying to show that for $n=2$, if $A\in\operatorname{SL}_2(\mathbb{Z}/m\mathbb{Z})$ then it suffices to show that there exists $B\in M_2(\mathbb{Z})$ such that $r_m(B)=A$ and $\gcd(b_{11},b_{12})=1$.


Is "double hashing" a password less secure than just hashing it once?

Is hashing a password twice before storage any more or less secure than just hashing it once?  What I'm talking about is doing this:  $hashed_password = hash(hash($plaintext_password));   instead of just this:  $hashed_password = hash($plaintext_password);   If it is less secure, can you provide a good explanation (or a link to one)?  Also, does the hash function used make a difference?  Does it make any difference if you mix md5 and sha1 (for example) instead of repeating the same hash function?  Note 1:  When I say "double hashing" I'm talking about hashing a password twice in an attempt to make it more obscured.  I'm not talking about the .  Note 2:  I know I need to add a random salt to really make it secure.  The question is whether hashing twice with the same algorithm helps or hurts the hash.


Showing $\int\limits_0^{\pi}\log(\sin(\theta))d\theta = -\pi \log(2)$

I have to show that  $$ \int_{0}^{\pi}\log(\sin(\theta))d\theta = -\pi \log(2) $$  This is a problem from the complex & real analysis qualifying exam.  This problem is maybe solvable by usual integration techniques but I strongly believe that they want us to prove it using complex analysis methods. Any approach will be appreciated.  I already tried with no luck:   $u = \sin(\theta)$ $u = \theta - \frac{\pi}{2}$ $\sin(\theta) = \frac{e^{i\theta} - e^{-i\theta}}{2i}$ and define a semi-circle that avoids $\{0\}$ and define a branch outsite that region (for example in the III or IV quadrants).


Install Ubuntu 16.04.1 amd64 on a Lenovo T61

Can I install Ubuntu 16.04.1 desktop amd64 on a laptop with Intel(R) Core(TM)2 Duo CPU T7100 @ 1.80 GHz and 2 Gb of RAM? I already have Windows 7 and it runs on 32 bit. I want to install Ubuntu along Windows 7 and using pictures, videos and books with both systems. Is it possible?


Is a spell with an attack roll "an attack" for the purpose of Sneak Attack?

Sneak Attack says:     When you attack a creature and hit, you can deal extra damage to that target if you have advantage against it or if another enemy of the target is within 5 feet of it and that enemy is able to take actions.   Emphasis mine. Now, suppose I am going to play a High Elf rogue, and select ray of frost as my racial cantrip. Since the ray's damage scales by level (unlike Rogue's standard physical damage progression, which is quite limited), I am thinking about Sneak Attacking with that spell, which nets into 8d6+5d8 plus 10-foot decrement of movement speed in the 20th level, if it's legal. Is this behavior correct? Are spells with attack rolls valid for making sneak attacks, like they were in 3.PF? If they do, does the added Sneak Attack damage assume the same damage type (e. g. cold for ray of frost) as the spell's damage type? Does allowing this give unfair advantage on my hypothetical High Elf rogue over other characters?


Is there any command that by using I can clean the cache in RHEL?  I used this command:  sync; echo 3 > /proc/sys/vm/drop_caches   but it didn't work.


my Biber don't creates the bbl file anymore. One week before everything worked just fine. I tried to install a fresh TeXLive (2020) distro on my laptop, but it doesn't work either. With TeXLive 2019 (which was installed on my laptop) it doesn't work either (error: ifluatex.sty not found). If I put the file manually in the folder the output is the same as with TeXLive 2020. I've already reviewed this posts and tried the solutions (spoiler: they're not working):          My System:  Windows 10x64 2004 19041.388 pdfTeX 3.14159265-2.6-1.40.21 (TeX Live 2020/W32TeX) biber version: 2.16 BibTeX 0.99d (TeX Live 2020/W32TeX) biblatex 2020/12/31 v3.16 Sublime Text 3.2.2 3211 LaTeXTools st3-4.0.0-alpha.9  MWE: \listfiles \documentclass{article}  \usepackage{biblatex} \addbibresource{ref.bib} \begin{filecontents}{ref.bib}     @Article{Foo,       author = {Guy, Some},       title  = {Some Title},       year   = {2021}     } \end{filecontents}  \begin{document}     This is a test.\cite{Foo}     \printbibliography \end{document}  I run pdflatex bib.tex biber --debug bib pdflatex bib.tex pdflatex bib.tex    Summary: biber --cache don't do the trick Changing the TEMP/TMP user-environment variables don't do the trick either. Tex-file is located in a non-special-character folder. With second machine it's not working either. Removing and (re)installing the biber package doesn't did the trick. Updated the whole TeXLive installation with tlmgr update --self --all --reinstall-forcibly-removed C:\Temp\mwe>kpsewhich biblatex.sty c:/texlive/2020/texmf-dist/tex/latex/biblatex/biblatex.sty


Translate the sentence into symbolic logic

You can fool some of the people all of the time, and you can fool all of the people some of the time, but you can't fool all of the people all of the time.    My attempt is   $$((\exists(x),A(x)) \land(\forall(x),S(x))) \land \neg (\forall(x), A(x))$$  Such that  $A(x)=$ You can fool all the time  $S(x)=$ You can fool some of the time  Just starting out basic logic and I'm looking to see where I"m making mistakes. Thanks


Why does the map in my controller always returns a nullpointerexception?

Controller.java  Map<String, String[]> formData  = request().body().asFormUrlEncoded();      if(formData.get("firstName") != null) {         JOptionPane.showMessageDialog(null, "not null");      }   When I click the save button after I run the program, it always returns an error message of NullPointerException even if I put a value in the firstName textbox.


Applied math PhD programs - no. of courses to counterbalance low GPA?

I’m about to turn 38 and after much research and consideration I have decided that I need to return to school. My goal is to apply to applied math PhD programs and work in industry, ideally working on problems in computational science or fluid dynamics.   My major (economics and math) GPA from a good public school was around 3.03 and my GPA for my math courses fell at 2.88. Previously I experienced some very serious issues in my life that played its role in this (not an excuse but just an unfortunate fact at the time).   I’ve reached out to some professors about my background and have been told that my GPA, though not considered the sole factor in determining admission, is a problem. I plan on applying to and enrolling in a post baccalaureate program at an Ivy league college near my home and plan on sitting for the math GRE subject test but I feel like I need to take more courses than I can afford to even be considered for such programs (the courses for the post bac. program are around $6K each).   I’m prepared to use a good bit of my life savings and working part time to fund this but I would like to learn how I can get a better sense of how many more courses I should take to counterbalance my low GPA.  Would graduate committees be open to giving an unofficial assessment of my background before applying? I don’t plan on applying to the elite schools because I feel that my GPA would knock me out regardless.   Some background on me:  Since graduating I’ve had varied work experience such as working as a math tutor to working in finance in the last 10 years. I also have a good bit of experience programming and have furthered my education to some extent for what it's worth: passed an online specialization course in R programming that spanned roughly 9 months, picked up a number of financial licenses, and even passed an actuarial exam when I was considering that route.   I do have course work in calculus, econometrics, ODEs, linear algebra, and an intro to analysis course.  Any thoughts/insights are definitely much appreciated.


"Covered with" vs. "covered in" vs. "covered by"

I want to find out the differences in meaning among covered by, covered in, and covered with.  For example, what is the difference between:     covered with blood   covered in blood   or the differences in meaning among     the mountain was covered with snow   the mountain was covered in snow   the mountain was covered by snow


Let $R$ be a topological ring and $R^\times$ the group of units. I read that $R^\times$ with the subspace topology from R does not make the multiplicative inverse map continuous. (Apparently one has to additionally require the map $R^\times \to R \times R$ (given by $x \mapsto (x, x^{-1})$ is continuous). What is a simple example illustrating this point (i.e. where giving the subspace topology makes the inverse not continuous)? For example for $R=\mathbb{Z}_p$ (p-adic numbers) I might be mistaken but I think the open neighborhoods of $1$ in $R^\times$ are $1+p^n\mathbb{Z}_p$, which is the subspace topology from $\mathbb{Z}_p$


Steps to reproduce issue:   Open the sliding menu, click on Edit to edit sites list. Click on drop down icon to get sites list and now it will show Up icon. Click on that icon (up) again, make sure you don't select any site. Now click on that icon, nothing happens!   Issue: If User don't select any site then it should change the state again to normal and allows user to select site(s).


What can cause headset bearings to become loose quickly?

On a new-ish CX bike (about 1 year old), I frequently need to adjust/tighten the headset bearings (semi-integrated ahead type).   After a few rides, they become loose which is noticeable by a "shuddering" feeling when using the front disk brake. Additionally, there is noticeable play in the bearings when I pull the brakes and move the bike back and forward.   What can cause the headset to become loose that quickly? What can I do about it? I already tightened all screws on the stem to spec (the label says "all max 8Nm") after tightening the adjustment screw, is there anything else I can try without specialized tools or replacing the headset?


Show that every mapping $f: X \to Y$ is continuous where $(X,d)$ is a metric space with the discrete metric

Let $(X,d)$ be a metric space with the discrete metric and let $(Y,d')$ be an arbitrary metric space. Show that every mapping $f: X\to Y$ is continuous.  I got a bit confused about this, initially, I thought that it would come quite directly from the definition, but I'm not sure how to proceed since I'm not given $f$ to work with. Perhaps there is some other definition for continuity that I'm not familiar? I've used the one that states $\forall \varepsilon >0 \ \exists \delta >0$ s.t. $d(x,y) < \delta \Longrightarrow |f(x)-f(y) | < \varepsilon.$


Data recovery from SSD after reinstalling Ubuntu

I have Ubuntu 16.04 installed on my PC (on SSD-500GB). I did an update using sudo apt update and rebooted the system. But when I tried to log in again I got stuck in a login loop and got a black screen. I did everything possible to remove that error (even purged the nvidia drivers) but failed.   So without any backup of my data I tried reinstalling Ubuntu from USB. I didn't format or delete anything. Now I can log in, but I've lost all my data which was on the PC's SSD. Is there any way to recover the data? Any software I can use to do that? Any help will be much appreciated.


Why can a particle decay into two photons but not one?

I recently read an old physics news about the Higgs boson where it was observed to decay into 2 photons and I was wondering why it wouldn't have decayed into a single photon with the combined energy of 2 photons?


SQL command or trigger needed to capture changes in tables

I want a query or trigger that will identify what changes done in the database tables from the Third Party Software such CMS etc. I want to check that which data is modifying with time. There is no log maintained in that Third Party Software so i want to check it thorugh SQL Server


Show that $\lim_{n\rightarrow \infty}\frac{a_1+a_2+\ldots +a_n}{n}=0 \iff \lim_{n\rightarrow \infty} \frac{a_{1}^2+a_{2}^2+\ldots +a_{n}^2}{n}=0$

Suppose that $(a_n)$ is a bounded sequence of positive numbers. Show that $\lim_{n\rightarrow \infty} \frac{a_{1}+a_{2}+.....+a_{n}}{n}=0$ iff $\lim_{n\rightarrow \infty} \frac{a_{1}^2+a_{2}^2+.....+a_{n}^2}{n}=0$. In this question, I proved $\lim_{n\rightarrow \infty} \frac{a_{1}+a_{2}+.....+a_{n}}{n}=0$ $\implies$ $\lim_{n\rightarrow \infty} \frac{a_{1}^2+a_{2}^2+.....+a_{n}^2}{n}=0$, by using A.M and G.M inequality. I tried to prove the reverse inequality, but stuck in every attempt. Can anyone suggest some hint for the reverse inequality?


I known how to package a jar to exe file using exe4j.   But now I also want to package the JAR with all required resources, such as html ,js files.   How can I do that?


MTG: Indestructible creature with both damage and -1/-1 counters

If let's say a 3/3 indestructible creature takes 2 combat damage and then 2nd main gets a -1/-1, does the creature die?  Am assuming no since its still technically a 2/2 indestructible with 2 damage on it and NOT a 3/1 indestructible with a -1/-1


What does it mean to "take from the community and never give back"?

page about suspensions uses some vague language and I am curious as to what it means by:  The user never gives anything back to the community, but only takes.


If all the roots of a polynomial P(z) have negative real parts, prove that all the roots of P'(z) also have negative real parts

If all the roots of a polynomial $P(z)$ have negative real parts, prove that all the roots of the derivative $P'(z)$ also have negative real parts.  Could anyone provide a proof for this please?


Why does oxforddictionaries.com not use a comma after the abbreviations 'i.e.' and 'e.g.'?

At , they don't use a comma after 'e.g.' and 'i.e.'.   Period is required after 'i.e.' here in BrE.  .  .  But we would use a comma after 'for example' and 'that is' in a sentence.  So why is the comma omitted after each abbreviation? This, logically, does not make sense.


Problems proving that a compact operator is completely continuous

I would like to prove that if $T:X\rightarrow Y$ is a compact operator, then for every weak convergent sequence $(x_n)_{n\in\mathbb N}$ with $x_n\rightharpoonup x$ for some $x\in X$ it follows that $Tx_n\rightarrow Tx$ with respect to the norm on $Y$.  I started the proof with,  Since $(x_n)_{n\in\mathbb N}$ is weak convergent there exists a positive constan $C$ sucht that $||x_n||\leq C$ for all $n$. Hence by compactness it follows that $Tx_n$ contains a convergent subsequence i.e $Tx_{n_k}\rightarrow y$ for some $y\in Y$. Now it should be somehow possible to deduce that $y=Tx$. But I am not able to move on.   Could someone give me hint how to proceed? or even how to find a better start for my proof?  Thanks in advance!


I've read all the explanations online. Use market to fill quick, regardless of price. But... How that is that different from a sell limit of 0 or a buy limit of infinity? (Right, in practice things can't so far without halting but the general idea stands.)  Why world anyone take the (albeit minuscule) risk of a market order (aka no limit limit order)? What's the point? Why not simply use limit orders, set to, say 10% or 20% of current? Do they execute differently in most cases where the prices don't take huge jumps quickly?  What am I missing? I've heard some users are charged less for a market order. Is that still true and causing this technically unneeded order type to be available and encouraged to all?


How do I reorder the rows of the shapefile in the file? I know how to order them in the attribute table view, but I need to actually switch up the order (by descending id) in the file itself.  It's a little weird but the reason being eventually it will be turned into a geojson and drawn up in a webmapping project but the way the webmapping API works, the draw order is naturally in the order that is in the file, and when icons get very clustered, I'd like items with the lower id to take priority (e.g. be on top / drawn last).  There's probably a way around that in the webmap API but I think it'd just be much simple to reorder the table.


Is there a way in latex to print the location of the file itself like in Word?

Word has the feature to print the path to the very file in e.g. the header or footer. How can I achive this with latex?  So, if the path to my document is  /home/user/tex/report.tex then I would like to have the path in the header or footer.


Staying in the Schengen area more than 90 days

We are planning to go travelling around Europe from July to November this year. As my partner is Canadian, we have been looking at ways to do this but I just want to check if this will be allowed…  We went to Copenhagen for 4 days on March 25th to start the 180 days. We then left the zone and are planning to return on the July 5th for a further 80 days. We then plan on going to eastern Europe for two weeks outside the Schengen zone, which then completes the 180 day cycle.  Would they then let us return to the Schengen area to start the 180 day process from the start to continue our travels?


I want to copy a visible file to a hidden folder.  In this case, I want to copy a program folder to the  /.wine folder


pass stdout fd to 'read' system call, but it still works fine

I pass 1(stdout)/2(stderr) to read system call but it still works fine. Then I pass 0(stdin) to write system call and find out it works too!  int main(int argc, char** argv){     char buf[1024] = "abcdefghi\n";      write(0, buf, 10);      char readbuf[1024] = {0};     // read(1, readbuf, 10); works too     read(2, readbuf, 10);     write(2, readbuf, 10);      return 0; }   output:  abcdefghi hey stdin  <-- I input this hey stdin   Confused, I thought it should be an error.   Experiement:   Then I tried redirecting fd 2.  $ ./a.out 2>/dev/null   this time both the read and 2nd write is not 'visible'. The output is  abcdefgi   So the stderr can be used for read?  I then close the stdout & stderr and make two copy of stdin:   int main(int argc, char** argv){     char buf[1024] = "abcdefghi\n";      close(1);     close(2);      dup2(0, 1);     dup2(0, 2);      write(0, buf, 10);      char redbuf[1024] = {0};     read(2, redbuf, 10);     write(2, redbuf, 10);      return 0; }   Again it works.   output:  abcdefghi hey stdin  <-- I input this hey stdin   So stdin can be used for write?  I need some explanation here.  Question  I want to know:  Why stdout/stderr can be used for read?  Why stdin can be used for write?  Is the three stream(stdin,stdout,stderr) internally one stream ?  If not, why am I getting this result?


I've been stuck on this problem for days. Could you help me?  "Let A,B,C,D be sets. A,B are not empty sets. Prove that if (AxB)U(BxA) = CxD, then A=B=C=D."


Storing output of shell script to variable

I have read many threads on this topic, but none of the solutions have worked for me.   I am trying to do the following:  RELEASE_COMMAND_OUTPUT=$(exec ~/temp/execs/github-release release --user patick --repo $REPO_NAME --tag $RELEASE_VERSION --name $RELEASE_VERSION --description "$DESC")   but the output of ./github-release is not stored in the RELEASE_COMMAND_OUTPUT variable.   I'm aware of the concept of , but none of the solutions I've tried have worked. What am I doing wrong?


How do the Attack and Defense stats work in Pokémon GO?

Every pokémon has 3 base stats: stamina, attack, defense. Stamina determines a pokémon's HP. However, I still don't understand what attack and defense do. If pokémon use moves that deal a fixed amount of damage (e.g. Vine Whip does 7 damage), why do attack/defense stats matter?   For example, Venusaur has a higher attack stat than Bulbasaur (198 vs. 126). Both of them can use Vine Whip. Wouldn't they both deal the same amount of damage? So why does it matter that Venusaur has a higher attack stat than Bulbasaur?  I feel like there should be some kind of equation that uses the attack stat of the attacker, and the defense stat of the defender in order to modify the damage in some way. Otherwise, these two stats seem irrelevant.  Note that I am not talking about Type Effectiveness or STAB. I know how those modify the damage. I'm asking about how the attack and defense stats that pokémon have modify the damage they do.     "V0001_POKEMON_BULBASAUR"   ...       Stats {         BaseStamina: 90         BaseAttack: 126         BaseDefense: 126   }   "V0003_POKEMON_VENUSAUR"   ...       Stats {         BaseStamina: 160         BaseAttack: 198         BaseDefense: 200       }


How to construct the URL for search with multiple input?

I am having a home page where I can search on multiple tags. How should I construct the URL? Suppose I search for tag = test_1 and tag = test_2  Should I construct the url like   http://www.example.com/tag/test-1,test-2   or  http://www.example.com/tag/?tag=test-1,test-2   or  www.example.com/tag/test-1-test-2   or  any other option?  I know query params are generally ignored by search engines and I should not put comma in URL so according to it "www.example.com/tag/test-1-test-2" is best option but I am afraid that www.example.com/tag/test-1-test-2 and www.example.com/tag/test-2-test-1 will generate the same result.


Declaring a Variable and using it inside a if statement

I just started with java and its doing realy good till now. But now i startet coding a little bit on my own. dont get the Problem here:  import java.util.Scanner;   public class Taschenrechner {      public static void main(String[] args) {          System.out.println ("Mein erster Java Taschenrechner");         Scanner scan = new Scanner (System.in);         System.out.println ("Welche Operation ? Möglich sind + - x /");         String operation = scan.nextLine ();         System.out.println ("Erste Zahl ?");         int input1 = scan.nextInt ();         System.out.println ("Zweite Zahl ?");         int input2 = scan.nextInt ();         int output = 0;          if (operation == "+") {             output = input1 + input2;         }          else if (operation == "-") {             output = input1 - input2;         }          else if (operation == "x") {             output = input1 * input2;         }          else if (operation == "/") {             output = input1 / input2;         }          System.out.println ("Das Ergebnis ist: " + output);      }  }   The variable output stays 0 and dont change  By the way...have i postet the code sampe the right way ?


How do I increase the inmargin in beamer?

I would like to do two things   Increase the size of inmargin area (i.e., customize inner sidebar so that more contents could fit there) Reduce the empty space between the title of block environment and the slide edge (from the example below, the title of block has too much of wasted space to its left which could be used to create more readable sentences)     MWE  \documentclass[xcolor={x11names}]{beamer}  \usecolortheme{structure} \useinnertheme{rectangles} \useinnertheme{inmargin}  \usecolortheme{crane}  \usefonttheme{structurebold}   \usepackage{fontspec}  \usepackage{calc}  \usepackage[inline]{enumitem} % Description list defaults      % To change font     \newcommand{\descriptionfont}{\fontencoding{T1} \fontfamily{bch} \selectfont}      % Label indentation     \newcommand{\descLabOffset}{\widthof{\hspace{2.6mm}}}      % Left of description aligned with the left margin     \newcommand{\descLeftLabMarInd}{0mm - \descLabOffset}      % Left of description aligned with \parindent     \newcommand{\descLeftLabParInd}{\parindent - \descLabOffset}      % Set the list options     \setlist[description, 1]{font=\descriptionfont, leftmargin=*, labelsep=3mm, labelindent=\descLeftLabMarInd, align=left}  \begin{document}   \begin{frame}{Induction Motors}      \begin{block}{Why is induction motor very common?}          Induction motors are very practical for the following reasons          \begin{description}             \item[Rigid] Rigid             \item[Cheap] Cheap             \item[Low Maintenance] Low Maintenance             \item[Self-Starting] Self-starting             \item[No Excitation Needed] No Excitation Needed         \end{description}      \end{block}  \end{frame}  \end{document}


"fixing recursive fault but reboot is needed" error

I am running a 64bit laptop and i am trying to install ubuntu 11.04 from both a usb and cd.  However, when I click either install from disk or try ubuntu I get to a black screen with this: fixing recursive fault but reboot is needed  Any ideas?


I had to remove Chrome to have enough space to upgrade from 16.10 to 17.04.  I downloaded the latest version from Google.  But when it opens in the Ubuntu Software Manager, and I click on "Install", nothing happens.


My son installed Ubuntu on my laptop for me to use I like it except my insulin pump only uses Windows. I know nothing about the structuring of the HD. I have the windows 2000 full installation disk and the Windows vista upgrade disk. I do not have a recovery disk cause my son didn't make one before uninstalling windows and putting Ubuntu on.   I believe it was due to windows crashing that he went to Ubuntu. I am using Ubuntu 12.04.


local minima vs saddle points in deep learning

I heard Andrew Ng (in a video I unfortunately can't find anymore) talk about how the understanding of local minima in deep learning problems has changed in the sense that they are now regarded as less problematic because in high-dimensional spaces (encountered in deep learning) critical points are more likely to be saddle points or plateaus rather than local minima.   I've seen papers (e.g. ) that discuss assumptions under which "every local minimum is a global minimum". These assumptions are all rather technical, but from what I understand they tend to impose a structure on the neural network that make it somewhat linear.  Is it a valid claim that, in deep learning (incl. nonlinear architectures), plateaus are more likely than local minima? And if so, is there a (possibly mathematical) intuition behind it?   Is there anything particular about deep learning and saddle points?


How to get proper "weighted" average of one column's data based on number values found in another column?

I'm trying to get the true average "position" in Google (as per Google Search Analytics data) for specific search query filters (e.g., all queries containing "xyz")  .  Where I'm getting hung up is that I need to take into account the total number of Impressions for each in the Impressions column (column D) to get a proper average.  Here is my current formula:  =AVERAGEIF($B$3:$B,"*"&B1&"*",$F$3:$F)   How can I create a proper average?


Show that $\mathbb{R}^2$ is not homeomorphic to $\mathbb{R}^2 \setminus\{(0,0)\}$

Show that $\mathbb{R}^2$ is not homeomorphic to $\mathbb{R}^2 \setminus \{(0,0)\} $.


How might I go about limiting the execution time of a command line program in windows? I know in linux there is timeout/timelimit available, but I have been unable to find similar utilities for windows.


Rigorous proof that surjectivity implies injectivity for finite sets

I'm trying to prove that, for a finite set $A$, if the map $f: A\rightarrow A$ is a surjection, then it's an injection.  I've looked at this post:  but the arguments there seem very round-about, proving that injectivity implies surjectivity first.  I think I've seen other proofs, too, but they all sound kind of flimsy.  They tend to go something like "If the function is surjective then no two arguments can go to the same image, since that would require some element of the range not being the image of any element."  While that's true and I see what the argument has in mind, it's no more convincing than the statement of the claim that we're trying to prove!  Without a more rigorous proof, both seem to rely on the intuition that everything has to go to one and only one thing, but we're supposed to be proving that.  But I've been trying to develop a more thorough and direct proof, and haven't been able to.  I've tried induction:     The theorem holds trivially if $|A|=0$.  Suppose the theorem holds up to $n=|X|$, and let $|A|=n+1$ and $f:A\rightarrow A$ be a surjection.  Then let $x\in A$ and $f^{-1}(x)$ be the set of all elements $y\in A$ such that $f(y)=x$...   But at this stage I want to restrict my function, but that has the disadvantage that if $f(y)$ has more than one element in it, when I pluck it out of $A$ as the domain and pluck $x$ out of $A$ as the range, then I may not be dealing with a function mapping from a set to itself and so I don't get to use the inductive hypothesis.  Any other proofs you know about?


Proving derivative is continuous using L'Hospital's Rule

Suppose that $h$ is continuous on $[a,b]$, differentiable on $(a,b)$, and that $c \in (a,b)$. Suppose also that $\lim_{x \to c} h'(x)$ exists. Prove that $h'$ is continuous at $c$.   I have found this answer here  but can't follow the process. Any help/detailed explanations would be REALLY appreciated! I'd rather use L'Hospital Rule instead of the Mean Value Theorem, but I can't follow how to go from one step to the other... Thank you!


How to add case related attachments on vf email template

I have walk through many questions and answers here which are not cleared.and getting Error: Invalid child of messaging:emailTemplate. Only messaging components are allowed as children of messaging:emailTemplate. <apex:repeat value="{!attachments}" var="attachment">     <messaging:attachment renderas="{!attachments[0].ContentType}" filename="{!attachments[0].Name}">     </messaging:attachment>     </apex:repeat>  ERROR like: Error: Invalid child of messaging:emailTemplate. Only messaging components are allowed as children of messaging:emailTemplate.


I'm trying to merge two user inputted lists that have been sorted in descending order. I understand how to merge two lists then sort, however i'm struggling the other way around. # user list input a = [int(x) for x in input("List 1: ").split()] b = [int(y) for y in input("List 2: ").split()]  a.sort(reverse=True) b.sort(reverse=True)  print(a + b)  For example, I want to input: [1, 3, 3, 6] &  [1, 4, 5], and my output be: [6, 5, 4, 3, 3, 1, 1]


Why rotating reference frames are not inertial?

Let's say I'm standing on the equator, and that there is no other reference point in the sky.  If the planet is rotating, then I measure my weight to be lower than if it is not.  But given that I have no reference frames to "prove" than I am rotating, why can't I just claim that my weight should be the same since I'm standing still and the universe is rotating around me?  (After all, this kind of argument does work for translation... so what's different about rotation?)


Pseudo random permutation function in c++

I'm looking for a couple of function that works in a similar fashion of srand(unsigned int) and rand(void) but, with a variable range instead of a fixed one.  I don't like the script  srand(time(NULL)); random_number = rand() % (h_limit - l_limit) + l_limit;   for two reasons. The first one is that a number can be repeated. The second one is that, for large limits, the probability density function is not a costant.  I think that a good solution could be redefine RAND_MAX that is the upper limit of classical functions. Is this a good way to solve my problem or there might be problems? Have you a better way to proceed?


Searching for Stack Exchange site by some word in name of site?

How, within any one of the Stack Exchange sites, or from the Stack Exchange site itself, do I search and find the link to a Stack Exchange site by title, versus by content of the questions inside those sites? Specifically, the end result of the search should not return links to particular questions in that site, but only to the links to the "top" of the site such as .  This is not the same as . That is a different (albeit quite useful) use case from this one.


What would be the derivation of the formula r=l/(1+ecosx) .

The 'r' represents the distance of a point on the ellipse with respect to the focus. The 'l' represents the semi latus rectum of the ellipse. The 'x' represents the angle at the focus and 'e' is the eccentricity of the ellipse.


Normal subgroup of a finite group of order 21

How many normal subgroups does a non abelian group $G$ of order 21 have other than the identity subgroup $\{e\}$ and $G$?  I think we can solve the problem using syllow's $p$-subgroups


BMO 2009/10 Round 2 Q.4 asks     Prove that for all positive reals $x,y, z$: $$4(x+y+z)^3 >27(x^2y + y^2z + z^2x)$$   My try:-  Using AM-GM, LHS is greater than $108xyz$. Using AM-GM, RHS is greater than $81xyz$. But I cannot think of how to proceed. Please help. Thank you.


Analog for 'side', but for front vs. rear

I wish to name a property that expresses whether something is in the front or at the rear.  This term has to be used together with 'side' without causing ambiguity.  Much like 'side' can be left or right, 'height' can be high or low, '????' can be front or rear.  Is there a word for that?


18.04 LTS: Download & install Adobe flash player

I should like to be able to download and install Adobe flash player on Ubuntu. I am not familiar with either Ubuntu or it's use of terms. I should be best regarded as a simpleton when trying to achieve anything with Ubuntu.  The version I have is 18. ?. This version is one of the type with long-term support. Many thanks, Geoffrey Lynn.


Do users understand this hybrid checkbox/radio control?

I'm wondering about the perennial problem that arises when presenting multiple options, where the user can select none, one, or several options.   Using checkboxes, it's not clear whether a user    intentionally selected none of the options or just ignored the question.   Like so:         – Wireframes created with  See. I don't know whether you don't like any fruit, or whether you just don't want to tell me.   So if I need to know whether the user answered the question, then it makes sense to include a "none of the above" option at the end of the checkbox list.  However, there's .  With a small number of options, ....          ...but with a larger number of options, radio buttons quickly become untenable:          So I was quite excited today to stumble across what might be a solution to the problem—a hybrid checkbox/radio control:          When the radio button is selected, the checkboxes become deselected, and when the checkboxes are selected, the radio becomes deselected.  At first glance, this looks like a great solution...but before I start adopting it, I want to check if it may confuse people. Perhaps they view the separate shapes as corresponding with separate questions; or perhaps they don't understand why clicking on some things (but not just any thing) may cause others to become deselected; or perhaps they don't distinguish between checkboxes and radio buttons at all and they're slowed down by wondering why one of the buttons is a different shape from the others.  Has user testing found that this control is commonly understood?  Are there particular demographics or psychographics that find this hybrid control problematic?


What is the appropriate usage of this Who's and What's to imply possession of a property

Consider the following sentences:   Please consider the person who's shirt is red.  Please consider the car what's bumper is blue.  Please consider the car who's bumper is blue.    Number 3 sounds wrong to me and number 1 sounds right.  A car cannot be a "who" unless its a work of fiction. The question here is whether or not number 2 is correct form. Is number 2 correct form? Why or why not? If not, what would be the correct form to refer to a specific inanimate object what's component is blue or based on some other criteria.  What rule specifies that it is correct or not correct.


Why does top report the incorrect CPU usage?

I have a machine with Intel(R) Xeon(R) CPU E5520 visible as 16 logical cores (8 with HT). If I run something to eat CPU time (single threaded) top correctly reports 100% CPU usage for the process but only around 3-4% total usage.   Cpu(s):  3.6%us,  0.0%sy,  0.0%ni, 96.4%id,  0.0%wa,  0.0%hi,  0.0%si,  0.1%st    PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND  1567 www       20   0 65632   84    4 R  100  0.0   0:05.96 burnMMX   Surely the reported usage should be ~6.25% (1 of 16 cores).   Is it incorrect because it's a virtual machine?  How could I calculate a correct value?


Making polygon from intersecting lines in QGIS using Polygonize or similar?

In QGIS, I want to make polygons from a set of intersecting lines. Looking at the screenshot here, I want chop the purple line (it's a closed line, not a polygon) where it crosses the green and blue lines. The result hopefully would be a polygon where I have hatched in red. I have quite a few to do.    I have tried the QGIS tool previously called Polygonizer (see ), but now called Polygonize. This is a tool that, given a layer containing a set of crossing lines arranged essentially like a # symbol, should create a polygon from the enclosed space in the middle.  (In QGIS 2.01, Polygonize is in the top menu bar: go to Processing -> Commander, then type "Polygonize" on the command line, select "Processing algorithm: Polygonize" from the list that appears, and press Enter.)   At the momemt Polygonize doesn't work properly. Is there another way to do what I want to do?   For example, wouldn't it be great if the QGIS 'Split Feature' command was able to work like MapInfo's 'Polyline Split', where you select the polygons to split, then select an already-drawn polyline to split by, and voila. But Split Feature seems not to work that way.    UPDATE: Detail of problems with running Polygonize.  I have 64-bit QGIS 2.01 installed to Windows 7 from the installer package, QGIS-OSGeo4W-2.0.1-3-Setup-x86_64.exe.  The routine processed an output from my shapefile, but did not create a polygon from the region enclosed by intersections between the blue, green and purple lines. (Note: in the actual input file, all these lines are on the same layer; the screenshot just colours them differently for illustrative purposes). What I got instead was a simple conversion of the purple outline to a polygon, as though the program completely ignored the blue and green lines.  When I node-edited the closed purple line, to open it so that I had a set of open crossing lines like in the # symbol, and then ran Polygonize again, nothing happened. No crash, but no visible polygon in the output file.    When I used Nick Hopton's own  data, I got a crash; see screenshot:


I have two problems. The first one is i cant enable my wireless broadcom driver. For that i need an internet connection. I tried plugging in the cable but it just shows like its connecting to wifi. My network interface is eno1. Im dual booting windows 10 and ubuntu 16.04. Btw it recognizes the device.  EDIT: shameless bump


Is $x^4+x^2+1$ an irreducible polynomial over $\Bbb Z/2\Bbb Z$?   According to  the answer is no. But I can't find the factors. Can you?


I was once told of a word describing how utterly overwhelmed you feel when looking at mountains. Not sure if the word describes the actual mountains, or how you feel


When I edit vertices they move in whole number rather than decimals

When I try and move some vertices, scale, extrude, rotate, all those things, it automatically makes it a whole number rather than decimals.  Sorry this is so hard to explain. Say for example a point I want to move is at 0 on x. When I try and move this, x will change to 1 rather than say 0.1. Then it will change to 2. So basically the intervals in which I move and extrude objects is different now.  Once again I'm really sorry for my poor explanation. I'm looking around in differnet settings but I don't even really know what I'm looking for. I'll try and provide a video if you do not understand what I'm saying.  Thank you!


A few years back our group tried to come up with the fastest possible D&D character. If I remember correctly we could build a character that could go faster than the , but I can't find my notes of this character ("The Running Man") anywhere anymore.   My question: what's the fastest D&D 3(.5) character possible?  The constraints we used in our experiment:   Has to be a "personal" speed: running, swimming, or flying (no mounts, vehicles, being shot from a cannon, etc). Max character level 20. No gold limit on items. Any Wizards of the Coast published rulebook allowed, including psionics. We did this experiment in D&D 3rd ed., but an answer in 3.5 is acceptable too (though I suspect that's tougher).   Basically, the question came down to creating a character that could make at least 6780 feet in a round (6 secs), which is 1130 feet per second, which is roughly 345 m/s: the speed of sound at about room temperature.  To further clarify the spirit of the question and the rules we had:   No "cheating" or obvious "shortcuts". This includes miracle/wish. I realize this is vague and invite anyone to edit my Question and make this constraint more explicit. Handbooks/rules on epic and deities are excluded.   So: how fast can we go?


my laptop has Ubuntu 16.10, with Spanish default language. I installed vlc by snap (to have the latest version 3.0). VLC works with the English language, how you can change the language ?, for more I look I find no option.


It would be nice if we could subscribe to an RSS feed of all the questions that match your 'favorite' tags i.e. an RSS feed of the questions that get highlighted as yellow when viewing the question list. You can achieve a similar effect by combining tags as described  and , however this is a pain to maintain, requiring the RSS URL to be edited in the feed reader if you start monitoring new tags, or stop monitoring old tags, also you have to worry about getting the syntax correct (c%23 instead of c# as an example). It would be much nicer if we could simply subscribe to a URL such as:  Then you could change the tags that are included in that feed from the ‘prefs’ subsection of the user account area.


I have a co-worker who manages a large MS Access database that contains X & Y fields for various locations he tracks.  We have previously exported the data to CSV and used the QGIS Delimited Text Plugin to plot the locations.  We would now like to be plot this data directly in QGIS by connecting to the MS Access db via an ODBC connection (as opposed to export to CSV).   Can QGIS consume the data from the ODBC connection to plot the X-Y locations? Can it be "live linked" to the ODBC connection so that when a project is re-opened, the layer "replots" all old and newly added locations dynamically (as opposed to exporting to shapefile, which would create a snapshot in time)? Can you create tabular ODBC connections that can be joined to spatial tables within QGIS?   You can do all of this in ArcGIS ("Add XY Data" tool), so it would be great if this capability existed in QGIS. I just cannot find anywhere that mentions its existence.  I am not planning to move to a spatial database.  As a GIS person myself, yes I know that it makes sense to move to a spatial database, and yes I have used PostGIS to manage this kind of data.  But these are not options right now.  The user is not a GIS person nor wants to be, and he manages his own database in MS Access and that will not change.  I am and am pulling him kicking and screaming into the GIS world and want to make it easy as possible.  He can live with exporting to CSV, I was just hoping there is a better solution USING ODBC FOR MS ACCESS and displaying the XY data in QGIS.


What to do when plagiarism is discovered

How should I act if I discover a user plagiarizing fellow users' posts? What if I find someone plagiarizing external resources without attribution?  See also:


This question is a very good question about LOLCODE code:   The formatting is pretty good except for the comments, which aren't formatted as comments.    I can see this being a popular formatting not only in Code Review but also in Programming Puzzles and Code Golf as well.  From looking at the  it seems as though it is catching on much like Brainf*ck did.


I have been trying for a long time to get this basic bit of code to work in a shell script, but to no avail, the code doesn't work!  read dec if [ dec="Y"]||[dec="Y"]||[dec="y" ]; then let repeat=1; else let repeat=0; fi done


jQuery $(document).on( eventName, selector, function(){} ) not working

I had a click function which functioned when I had this elements hidden on page load, and then showed them later. Now I am appending those elements on click after the page has loaded, and the function of course doesn't work. I thought I would fixed the problem with load() function but it still doesn't work. This is the html I append on click:  $('#magazine-detail')[0].innerHTML = '

Neste utgivelse

Forrige utgivelse

<button class="button primary expand">Kjøp abonnement - 1 måned gratis</button><button class="button secondary expand">Bla igjennom arkivet</button>

';   There I create #forward and #back elements, for which I have functions on click in my script:  $(document).ready(function () {     var imagesIndex = 0;     nextImage = 0;     loadedImages = new Array();      function preload() {         for (i = 0; i < 2; i++) {             if (nextImage < images.length) {                 var img = new Image();                 img.src = '/imagecache/cover/' + images[nextImage];                 loadedImages[nextImage] = img;                 ++nextImage;             }         }     }      $('#forward').load('click', function() {       imagesIndex++;       preload();        if (imagesIndex > (loadedImages.length - 1)) {           imagesIndex = loadedImages.length - 1;       }        $('#image').attr({"src" : loadedImages[imagesIndex].src, "alt" : name});     });      $('#back').load('click', function() {         imagesIndex--;          if (imagesIndex < 0) {             imagesIndex = 0;         }          $('#image').attr({"src" : loadedImages[imagesIndex].src, "alt" : name});     }); });   I have tried with:  $(document).on('click','#forward', function() {       console.log('entered');       imagesIndex++;       preload();        if (imagesIndex > (loadedImages.length - 1)) {           imagesIndex = loadedImages.length - 1;       }        $('#image').attr({"src" : loadedImages[imagesIndex].src, "alt" : name});     });      $(document).on('click','#forward', function() {         imagesIndex--;          if (imagesIndex < 0) {             imagesIndex = 0;         }          $('#image').attr({"src" : loadedImages[imagesIndex].src, "alt" : name});     });   But nothing gets logged when I click on the element.


What is the relation between Lille Europe and Lille Flandres railway stations?

I am checking the Belgian rail website for traveling to Lille. I get two options in Lille: Lille Europe and Lille Flandres.  What is the difference between these two stations? I suppose location, but is one served by more trains than the other? Do all trains stop in both? Are they completely unrelated meaning some trains go to one, others go to the other?  Which one should I pick to    Be near to the center? Get transport to the airport?


D&D 5e and "Theatre of the Mind" in combat

Our target play style for combat encounters would be to use battle boards roughly half the time (when there is enough of interest in play that the tactics are fun to play out), and to skip that with faster "cinematic" combat otherwise.  We have not been 100% successful. The problem is the numbers-driven descriptions in the rules. Needing to be "adjacent" (within 5 feet) for abilities such as Protection style fighting, ranged weapon ranges, spell effects and movement speeds are all much easier to resolve on a grid. Running those rules without a board rapidly devolves into sketches with numbers written on them and/or "mother, may I?" style of play because the DM needs to rule who is next to who, and which monsters are in the spell radius. These rulings also quickly get out of sync with player expectations when there is no map and we want to run combats quickly.  It doesn't help that the numbers involved come in pretty much all multiples of the base 5 feet. There is no obvious close/short/medium for effects and ranges. If there were such then I think it would be much easier for the DM to categorise and hand-wave things.  I was hoping that both board-based and no-board style of play would feel equally viable. But the focus on numbers seems to push toward board playing, at least for my group.  We would still like to pay heed to the differences in movement, range, area-of-effect etc of the rules in play. At least in the general sense of creature X is faster than creature Y, or weapon/spell A has better range than weapon/spell B.  Going beyond "just don't sweat the details", how can a group like mine play with the D&D 5e rules as written, without a map, but without leaning on the DM to resolve all our questions of "So, am I next to the Paladin?", or "Is it in range?"      Clarifying: "just don't sweat the details" is a welcome approach to solving the problem, but please give some examples of how this works in practice; i.e. which details can be removed and how?


I have created this image in Photoshop:    Layers:    I would like to save this arrow to a .jpg file without the white background rectangle. How can I achieve that? I was trying to hide the background layer before saving, but this doesn't help.