What is the difference in the two notation?
Difference between $\Delta$, $d$ and $\delta$
How can you get the names of method parameters? If I have a method such as:  public void MyMethod(int arg1, string arg2)   How would I go about getting the actual names of the arguments? I can't seem to find anything in the MethodInfo which will actually give me the name of the parameter.  I would like to write a method which looks like this:  public static string GetParamName(MethodInfo method, int index)   So if I called this method with:  string name = GetParamName(MyMethod, 0)   it would return "arg1". Is this possible? How to Screen Sharing / VNC to an iMac without waking the display? I have an iMac mid 2011 at home. When I was not home, I may need to access my mac with Screen Sharing. However the iMac display will turn itself on when I connect via Screen Sharing. The problem is I don't want to scare my family at home (with the elders and kids) as the iMac "turn itself on suddenly".   This is a problem specific for iMac. On MacBooks (Pro, Air, whatever) I can set the brightness to the lowest setting so the screen is black (i.e. the LED light is off). However on an iMac you cannot turn off the LED backlit by setting brightness. The display is still bright and everything is clearly visible even on lowest brightness setting.  Therefore these solution are not working as the display will turn on as soon as you move your mouse or hit any key on the keyboard via Screen Sharing.   Sleep Display (by Ctrl+Shift+Eject) Using the code listed on    Question: Is the a way to keep the iMac display off entirely while you accessing it with Screen Sharing? Test if there are files matching a pattern in order to execute a script What does it mean to instantiate a trait? I'm wondering whether it's possible to downgrade sfdx-cli to use an earlier version?  I'm trying to debug an issue with using it in pipeline scripts.  When I run sfdx version --core I get sfdx-cli 7.28.7 (core) .    If I run  sfdx version I get  sfdx-cli/7.28.7-7bceba6f24 darwin-x64 node-v10.15.3 .  If I do cat package.json inside the actual package dir for sfdx-cli after doing npm install sfdx-cli@7.26.0 I get  "sfdx-cli": "^7.26.0"  Why does it then show that the version is 7.28.7?  How can I force the lower version to have preference?  I do understand that this question is not really salesforce specific but hopefully someone has run into the same problem. Show that $Kf(x,y)=\int_0^1k(x,y) f(y) \,dy\\$ is linear and continuous Let $k:[0,1]\times[0,1]\rightarrow \mathbb{R}$ continuous and $K:C[0,1]\rightarrow C[0,1]$, given by $Kf(x,y)=\int_0^1k(x,y) f(y) \,dy\\$. Prove that $K$ is continuous. I try to see continuity in $0$, but i can't find $\delta$. This is a homework problem for my real analysis class. It is problem 13.1 from Mattuck's Introdution to Analysis. The question reads:       Suppose F(x) is continuous on some open interval I and c is a maximum point inside this interval. Is it true that f(x) must be increasing immediately to the left of c and decreasing immediately to the right of c? Proof or counterexample. (Note: A constant function is considered to be both increasing and decreasing.)      My friend and I have been attempting to find a counterexample. We figured a function that begins oscillating infinitely many times near c but converges to c would work. We're having difficulty constructing such a function out of elementary functions so we think we will have to define it in another way, piece-wise using receding intervals. I have no clue how this would look. Any advice would be greatly appreciated. I wanted to remove and reinstall the software-center package.  I removed it, but now I can't reinstall.  I tried these commands without success:  sudo apt-get update sudo apt-get install software-center   How can I reinstall software-center?    When I performed the install command this is what I got:  $ sudo apt-get install software-center Reading package lists... Done Building dependency tree        Reading state information... Done Package software-center is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source  E: Package 'software-center' has no installation candidate Want to set a guest session password for login. How do you do this after skipping it at OS install? Best way to remove file extension from a string? So, I'm using a script I've made to convert videos to the webm format. A certain program calls the script, sending %f which is the full, absolute file name of the video, like this:  converter.sh %f   where %f has two possible extensions, .avi or .mpg.  # /bin/bash ffmpeg -i $1 `dirname $1``basename $1 avi`webm &amp;&amp; rm $1   It currently works perfectly when $1 contains a .avi file, because basename removes the .avi extension. When $1 ends with .mpg instead, the result is .mpgwebm.  How can I modify that script to be able to receive those two possible different formats?    Resuming: If $1 is /somedir/video.avi, the script should do:  ffmpeg -i /somedir/video.avi /somedir/video.webm   And if $1 is /somedir/video.mpg, the script should do:  ffmpeg -i /somedir/video.mpg /somedir/video.webm   I know this might be fool for some people, but I'm kind of new with the bash. Access gnome-shell messaging tray using keyboard Is there a keyboard shortcut to access the gnome-shell messaging tray? E.g. For responding to incoming IM, etc. How can I create a Chatter File via Apex? From the Chatter tab I can go to 'Files' and then upload a file without attaching it to anything.   I am wanting to know if there is a way to achieve the exact same thing via Apex? Emacs: Symbol's value as variable is void What does f-stop mean? There is a hint to show that if there were points in $\mathbb{Q}$, then there would exist $r,s, t \in \mathbb{Z}$ with $\gcd(r, t) = 1$ such that $2s^2 = t^4 - 17r^4$ , and then show that any prime dividing $s$ is a quadratic residue modulo $17$.  I'm stuck on the first bit - if you suppose $\left(\frac{a}{b}, \frac{c}{d}\right)$ is a point on the curve in $\mathbb{Q}$ (so $a, b, c, d \in \mathbb{Z}$) then you get to $2a^2d^4 = b^2c^4 - 17b^2d^4$, but I'm not sure where to go from here since you don't know that $b$ is a square? Inserting newlines in Rectangle Text elements via ArcPy causes overlap? I ran across an issue the other day when I tried to use ArcPy's mapping module to edit rectangle text elements with newlines (\n) in an ArcMap document.  Here's what the output looked like:    Here's the code I used to generate that output.  The first column are rectangle text elements Text1, Text2, Text3 going down; the second column are "plain" text elements Text4, Text5, and Text6 going down.  import os import arcpy  HomeDir = r"C:\Desktop" arcpy.env.workspace = HomeDir  CurrentMXD = arcpy.mapping.MapDocument(r"C:\Desktop\TextTest.mxd") OutputFilename = r"C:\Desktop\TextTest.pdf" if os.path.exists(OutputFilename):     os.remove(OutputFilename)  for TextElement in arcpy.mapping.ListLayoutElements(CurrentMXD, "TEXT_ELEMENT"):     TextElementName = TextElement.name      String1 = "The quick brown fox jumped over the lazy dog.\nShe sells sea shells by the sea shore."     String2 = "The quick brown fox \njumped over the lazy dog.\nShe sells sea shells by the sea shore."     String3 = "The quick brown fox jumped \nover the lazy dog.\nShe sells sea shells by the sea shore."      if TextElementName == "Text1":         TextElement.text = String1     if TextElementName == "Text2":         TextElement.text = String2      if TextElementName == "Text3":         TextElement.text = String3     if TextElementName == "Text4":         TextElement.text = String1     if TextElementName == "Text5":         TextElement.text = String2     if TextElementName == "Text6":         TextElement.text = String3  arcpy.mapping.ExportToPDF(CurrentMXD, OutputFilename)   So far, it looks like the presence of the messed up text depends on whether the line is longer enough to wrap, and whether the line before the newline is longer than the line after the newline.  Any ideas about what could be going wrong?  Is there a workaround?  I could use plain text elements and worry about wrapping lines using Python, but I'm hoping I can figure something out. I have been looking at the plugin API a bit more in depth recently and I was wondering what real differences there were between action and filter hooks. They both are events that receive data as a parameter and they seem to both be able to do the same things.  Obviously I see that actions are called when actions take place and filters are called when data is manipulated, but it seems to just be a semantic naming difference.  Besides semantics and what they are used for, what real differences are there between them? I created a new profile for gnome-terminal and I can switch between &quot;Implicit&quot; profile and the new created profile as you can see in the below image:  Now I wonder how can I switch between profiles using a command-line/script or maybe using a shortcut for this.  Note: Solutions like: gnome-terminal --tab-with-profile=Implicit &amp;&amp; exit   are excluded because I prefer not to close and open another terminal or get another terminal window in this process of changing the profile. I saw that it has been already reported that also they have earned courious badge but the badge has not been given. but their answers say that they must wait a day and the badge will be awarded.  In my case its 8/5 and it was 5/5 long time ago and I have never received a message telling that I have earned it. its just telling me that the next badge to be awarded is Curious badge.  this is my profile: If $R$ is an integral domain and a subring $S$ has identity $1_S$, how would you show that $1_S=1_R$ (here $1_R$ is the identity of the ring $R$)? I am unsure about what an integral domain really is and how the subring comes into play here.