I cannot install updates and software in 16.04
How do I refresh the package list?
How do I Uninstall Windows 10 or Windows 10 preview? I joined in the  and I don't like it. However, this question may also be relevant to those who install the full version of Windows 10.  How can I downgrade back to Windows 8/7 from Windows 10 or Windows 10 preview? When is the vector space of continuous functions on a compact Hausdorff space finite dimensional? I know that the vector space of all real valued continuous functions on a compact Hausdorff space can be infinite dimensional.  When will it be finite dimensional?  And how will I identify that vector space with $\mathbb{R}^n$ for some $n$? Difference between "asked" and "were to ask" in conditional sentences? If $I$ and $J$ are ideals in a ring $R$ with $1$ such that $I+J = R$, show that $I^m$ and $J^n$ are co-maximal for all $m,n \in \mathbb{N}$ If $I$ and $J$ are ideals in a ring $R$ with 1 which are  co-maximal, i.e $I+J = R$, show that $I^m$ and $J^n$ are co-maximal for all $m,n$ in $\mathbb{N}$  Work done:     Should I proceed using    By taking $$K=I^m+J^m \neq R$$  Let $$S=\{I,J \in R \mid I^m+J^n \neq R \}$$ be the required partially order set ordered by inclusion then  $$I+J \subseteq I^n+J \subseteq I^n+J^m \subseteq \ldots $$  Then, I think this chain doesn't have an upper bound...as $I^m+J^n \neq R$ for all $ m,n \in \mathbb N$. Am I right??  Thanks for any help!! What does [&] mean before function? Is there any scientific experiment that can lead us to conclude we live in 3 spatial dimensions without the premise of the conception of limited dimensions?  Thank you all who helped in the improvement of this question (which was not clear at first).   EDIT:  I know that this can be a little philosophical, but it is also a scientific question.  Let's consider the scenario where the mankind was not ever able to see.  Let's also consider that this limitation could be surpassed thus not limiting us to reach a scientific and technological knowledge "similar" to what we have today.  Would this civilization of blind people reach the conclusion that they are living in a 3D spatial world?  Is the sense of touch enough to reach that conclusion? Is there any scientific experiment that can lead us to that conclusion without the premise of the conception of limited dimensions?  Would it be easier, harder, or just different to reach a conclusion predicted by the M-Theory? (please do not focus only on this last question) What, if anything should one do if a user's "about me" profile section contains extremely inflammatory terms (racist, etc.) I don't think anyone wants to be the thought police, and I'm particularly wary of censorship on a part of the site that is a user's personal self-statement, and is a little off the beaten path.  On the other hand, I'm also concerned that we may not want a site where clicking on a user to see their other posts would expose folks to racist or other bigoted terms that almost everyone would agree are inappropriate for civil discourse.    Don't forget the "be nice" rule".  Note that I don't want a "flag user" rule, which I know has been beaten to death already, and further think that swears and semi-inflammatory opinions, etc. should generally just be ignored - I'm only asking about terms that provoke serious emotions around racial, religious, ethnic, or sexual orientation issues.  What, if anything, is the appropriate response in such cases? show that $x$ is in $\ell^1$ if $\sum x_ny_n$ is convergent for all $y=(y_n)\in{c_0}$ If $x=(x_n)$ is a sequence of complex numbers such that the series $\sum  x_ny_n$ is convergent for all $y=(y_n)\in{c_0}$. Then prove that $x\in{\ell^1}$. Can anyone tell me what is the meaning of $c_0$  in this question and how to proceed on proving it. In my question's preview, the attached image looks rotated. So, assuming you are able to see it in the real orientation, can anyone determine what is that dust flake type thing on the top, slightly towards the left?   One looks like a dust flake and there's another dot to the left of it?  Note: I wont have physical access to the camera until the weekend.  Is it just a dust flake on the lens or can it be some problem with the sensor? Its a 3 month old Canon 1500D. Visa for transit in Seoul How to get PHP 7.0 running with Apache2 I am totally new to Linux, servers and websites. I recently set up Apache2, Python, PHP, and MySQL for setting up a LAMP server. I am using Xubuntu 16.04 and PHP 7.0.11. I followed a guide and placed a PHP file named testing.php in it with:  &lt;?php phpinfo(); ?&gt;    It doesn't show anything on localhost/testing.php All it shows is the code itself. It's a shame to type out an entire question, press post and then:     Sorry, you are only allowed to ask 50 questions in a 30 day period   Could you put some sort of notice on the page itself before submitting it to let you know the question won't be going through?  Or perhaps tell me how many questions I've asked in the last 30 days if it's >0?  Edit  This is not a complaint or statement about the limit, just a request that the error handling be done in a slightly better way to save people a lot of time. Tools for automating document compilation A lot of people write makefiles that say something like  paper.pdf: paper.tex         pdflatex paper         bibtex paper         pdflatex paper         pdflatex paper   To handle re-running TeX to get new/changed references and so forth. Is there a better way to do this? Product and Box Topologies I am having a hard time understanding why the box topology is finer the the product topology. Of course I know that with finite product, the two are the same. With product topology, the basis elements are defined so that the $U_{\alpha}=X_\alpha$ except for finitely many $\alpha$. So how can this topology be contained in the box topology which has only the product of the  $U_{\alpha}$ as basis. I think it should have been the other way round. Am I missing something here? I need help with this because I have been confused over it for a long time. Lightning-Web-Components Select Option prepopulate value Let's say I have a Lightning-Web-Component with a select list with dynamic options where the value is a user Id and the label is the user's name:  &lt;select class="slds-select" onchange={handleSelectChange} disabled={isDisabled}                           data-value={step.selectedUser} &gt;                                 &lt;option value=""&gt;--None--&lt;/option&gt;                                 &lt;template for:each={step.approvalTemplateStep.Approval_Step_Users__r} for:item="user"&gt;                                     &lt;option key={user.key} value={user.User__c}&gt;                                         {user.User__r.Name}&lt;/option&gt;                                 &lt;/template&gt;                             &lt;/select&gt;    How do I prepopulate the select option with a value? I have the value I want to be prepopulated in the variable called step.selectedUser.  Here's what I see on page load:   Here's what I should see: Two question on harmonic function How to populate the geometry column in a PostGIS table? After loading a polygon shapefile into PostGIS, the geometry column (geom) is blank for several features. In one case, only a single feature has the geometry calculated and all others are blank. I'm using the PostGIS SHP and DBF loader v.2.0. I am creating a spatial index, and using COPY rather than INSERT. I have loaded several other point datasets and they geom column is populated just fine... (Otherwise, things are working just fine for the polygons: when I create a new feature, the geometry is calculated / geom field populated...etc.) Have I done something wrong when importing the data?  Solution by @ThomasG77 (in comments) PgAdmin3 [doesn't] display features that are too complex but they are present.  You can try SELECT length(ST_astext(the_geom)) from your_table to confirm or you can find &quot;true&quot; empty geometry with SELECT * from your_table WHERE the_geom IS NULL;. ‘ld: warning: directory not found for option’ Different Google Searches return different titles for the same page I have a string "1112224444' it is a telephone number. I want to format as 111-222-4444 before I store it in a file. It is on a datarecord and I would prefer to be able to do this without assigning a new variable.  I was thinking:  String.Format("{0:###-###-####}", i["MyPhone"].ToString() );   but that does not seem to do the trick.  ** UPDATE **  Ok. I went with this solution  Convert.ToInt64(i["Customer Phone"]).ToString("###-###-#### ####")   Now its gets messed up when the extension is less than 4 digits. It will fill in the numbers from the right. so  1112224444 333  becomes  11-221-244 3334   Any ideas?