Can't restore lost windows partition
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How many points in RSA, such that $m^e = m \bmod n$ For every RSA-cryptosystem, there exist some messages $m$, for which it holds that $m^e \equiv m \pmod n$ As to the question, how many such messages exist, this question has already been asked and answered here:  However, I do only understand the answer up to a certain point Suppose that $n$ is only 1 prime. Then it holds that the number of unconcealable messages is $\gcd(e-1, p-1)+1$ This is because in $m^e \equiv m \pmod  p$ , either $m = 0$ or $m \not= 0$. In the latter case $m$ can be expressed as $g^t$, where $g$ is a Generator in $\mathbb{Z_p}$ $g^{t*e} \equiv g^t \pmod p$ $g^{t(e-1) \bmod p -1 } \equiv g^{0 \bmod p -1} \pmod p$ $t(e-1) \equiv 0 \pmod {p-1} $ has exactly $\gcd(e-1, p-1)$  solutions, so the total number of unconcealable messages is, together with $m=0$ , $\gcd(e-1, p-1)+1$ When we now look at real RSA, which has two prime factors in its modulus, it holds that the number of unconcealable messages is $(\gcd(e-1, p-1)+1)\cdot(\gcd(e-1, q-1)+1)$ Why is that so? I suppose it has to do with CRT, but I just cant understand why. I just wrote an answer to , which was trying to find numeric strings with or without commas (e.g. 1,234,567.89). I wanted to be thorough because I've seen this problem a lot, both on SO and in real-world code.   When I finished, I found 7 other new answers waiting for me, mostly variations on each other. Which would be fine, except for one thing: They're garbage answers. Unless I'm severely mistaken, every answer but mine (so far) is deeply flawed, and I want to downvote all of them. Yeah, I'm a stickler on regex, but IMHO if your pattern lets stuff like  ...,.,,.,,..9 or even ... pass as "numeric input," then you've failed to meet even the bare minimum requirements.  Enough venting. The reason I'm whining to Meta about this is that I'm about to do something that'll REALLY look like tactical downvoting, and I'm mildly concerned about the consequences. If I answer a question and then rain downvotes on every competing answer, will I get flagged for abuse? That would certainly seem like suspicious behavior to me.  More of an opinion question: At what point does a semi-correct answer deserve a downvote? Obviously, if it were just a typo, I'd edit it myself. Where's the line between "close enough" and "this answer sucks?"  Basically, is it just me? You've seen the question; am I right that these answers deserve downvotes? Seven people thought that [0-9,.]+ was good enough to declare something a number, so why am I the only one who doesn't?    Note: I found some related questions, but nothing that seemed like a duplicate:    - More of an etiquette question, plus the voter hadn't posted his own answer.  - I guess this pretty much covers my second question.   Also, as some have noted, my answer ended up pretty long and thorough. I put in a lot of effort because, with all this talk about how the other answers sucked, I wanted to be extra sure mine didn't. I don't expect pages of detail in a normal SO answer. Why is $\frac{d^n}{dx^n}(y(x))$ the notation for the $n$th derivative of $y(x)$, instead of $\frac{d^n}{d^nx}(y(x))$? I've always wondered why the numerator is $d^n$ while the denominator is $dx^n$ instead of $d^nx$ like the numerator.  I must be missing something very obvious or fundamental. Is this notation derived from the chain rule in some way? How to escape quotes in shell? Are keywords in URLs good SEO or needlessly redundant? A coworker and I are locked in a debate over the value of SEO keywords in the URL of a page. She wants to change all the filenames of the HTML pages of a fencing company so they look like residential-home-chicago.html, contact-chicago-contractor.html, and so on. She is convinced that because Google highlights keywords in URLs in search results, that means that putting keywords here is more valuable.  My position is that these do not improve SEO, since Google doesn't seem to give keywords in the URL any more weight than keywords in the body of the page, and . In the meantime, they make it harder for me to find the pages I want when its time to edit them, and the site as a whole looks cheap and spammy.   suggests to me that yes, keywords in URLs are useful, but not superior, and that they are more useful for human readability than search engine rankings.  I'm looking for authoritative sources that support either position, not blog articles from SEO optimization companies trying to promote themselves. How can I hide my code in visualforce page? Is it possible to simulate key press events programmatically? Is it possible to simulate key press events programmatically in JavaScript? Bash script to remove the oldest file from from a folder I want to make a bash script to delete the older file form a folder. Every time when I run the script will be deleted only one file, the older one. Can you help me with this? Thanks Extra semicolon near answers header On all the SE sites that I checked, the text that normally says something like “1 Answer” now says “1 Answer;” (with a semicolon seemingly in superscript):    The HTML for that part of the page looks like this (the semicolon is on the fourth line from bottom):              &lt;div id="answers"&gt;                  &lt;a name="tab-top"&gt;&lt;/a&gt;                 &lt;div id="answers-header"&gt;                     &lt;div class="subheader answers-subheader"&gt;                         &lt;h2&gt;                                 1 Answer                         &lt;/h2&gt;                         &lt;div&gt;                             &lt;div id="tabs"&gt;         &lt;a href="/questions/18587301/which-is-good-il-editor?answertab=active#tab-top" title="Answers with the latest activity first"&gt;             active         &lt;/a&gt;         &lt;a href="/questions/18587301/which-is-good-il-editor?answertab=oldest#tab-top" title="Answers in the order they were provided"&gt;             oldest         &lt;/a&gt;         &lt;a class="youarehere" href="/questions/18587301/which-is-good-il-editor?answertab=votes#tab-top" title="Answers with the highest score first"&gt;             votes         &lt;/a&gt; &lt;/div&gt; ;                         &lt;/div&gt;                     &lt;/div&gt;                 &lt;/div&gt; Assign the results from a Solve to variable(s) Ifstream read function doesn't load into vector Drawing line less than one pixel thick requires anti-aliasing in Android 4.2 How to undelete a directory that was just deleted with "rm -R" command (in cloud drive)? I deleted an important directory with rm -R command. This is an very populer host data. It was located /var/zpanel/hostdata/ayrintilih After remove ayrintilih directory has gone everything.  I tried to undelete with ext4magic program. But it need to another hdd volume for recovery.  Error message:   ERROR: can not use "/root/recoveried" for recover directory. It's the same filesystem : "/dev/dm-0"   My ISP just replied my request:  Unfortunately there is no way to add another Volume to a virtual Instance.  If it would be a dedicated Server, we could do it, but not in a Cloudserver.  You could try to minimize the partition and create another one, that would  count as another Volume. We also recommend to have allways a  Backup for your Important files. I'm currently typing a mathematical document which counts many sum symbols. I frequently use the align environment to render equations, although the default behaviour of this environment is to render the equations in displaystyle, which in my opinion wastes vertical space. I therefore have added \textstyle at the beginning of each line of math in this environment, but I'm looking for a more convenient solution.   So is there an environment that is similar to align with the exception it displays textstyle math by default ? Thank you. Whenever I read about the curvature of spacetime as an explanation for gravity, I see pictures of a sheet (spacetime) with various masses indenting the sheet to form &quot;gravity wells.&quot; Objects which are gravitationally attracted are said to roll down the curved sheet of spacetime into the gravity well. This is troubling to me, because, in order for objects on the locally slanted spacetime sheet to accelerate, gravity must be assumed. Therefore I ask; does the explanation of gravity as the curvature of spacetime assume gravity? If yes, what is the point of the theory? If No, what am I missing? Symmetric Matrix , Eigenvectors are not orthogonal to the same eigenvalue. I know that the symmetric matrix has orthogonal eigenvectors corresponding eigenvalues. Also, the eigenvectors from the same eigenvalue are linearly independent.  I need an example of symmetric matrix such that the eigenvectors from the same eigenvalue are not orthogonal.  Also, I know that the eigenvalues of the symmetric matrix are real. But , this statement true iff the entries are real numbers.Right? Since the matrix 2x2 $$A=\begin{bmatrix} 1 &amp;i \\  i &amp;1  \end{bmatrix}$$  has non real eigenvalues Google spreadsheet sorting messes up cell comments I'm running into this weird problem with Google spreadsheets: if the cells have comments on them and I sort the spreadsheet, the rows sort but the comments stay in the same position, and don't move with the cells they're attached to.  In other words, the cells look like this:  A C  &lt;-- comment on this cell B   and then I sort by this column:  A B  &lt;-- comment remains on this cell (stays in position) C  &lt;-- comment should have remained attached to this cell   This means that sorting is completely broken and I can't use it at all, because I clearly need the cell comments to stay with the cell they're attached to.  Is this a bad bug in Google Spreadsheets, or am I missing something here? How to install networkx python in QGIS? How to install and how to compile networkx python on QGIS?  I always get an error that no module named networkx in the console of QGIS I copied the file networkx in C:\Program Files\Quantum GIS Lisboa\apps\Python27\Lib\site-packages and there are not change. Making sense of principal component analysis, eigenvectors & eigenvalues Some verbs are followed by ing, e.g. I enjoy swimming. We can't say I enjoy to swim. Likewise, some verbs are followed by to, e.g. I decided to make a plan.   Which particular verbs are followed by ing and to? Can you please provide a list for that?  Moreover, which verbs can be followed by both without having the meaning changed?