I know I'm probably missing something really obvious, but I've tried   display: block; and margin: 0 auto;, and the inner div is not centering horizontally within my parent div?    .row-fluid-wrapper.row-depth-1.row-number-3 {   display: block;   margin: 0 auto;   text-align: center;   border: 1px solid red; }  .row-fluid {   width: 100%;   display: block;   margin: 0 auto; }  .row-fluid [class*="span"] {   margin: 0 auto;   border: 1px solid blue;   display: block;   float: left;   min-height: 28px;   margin-left: .2%;   box-sizing: border-box;   height: 150px; }  .row-fluid .span4 {   width: 31.914893614%; } &lt;div class="row-fluid-wrapper row-depth-1 row-number-3 "&gt;   &lt;div class="row-fluid "&gt;     &lt;div class="span4 widget-span widget-type-custom_widget "&gt;       &lt;div class="cell-wrapper layout-widget-wrapper"&gt;         &lt;span&gt;   &lt;div class="clearfix cta-wrapper"&gt;           &lt;div class="cta-text"&gt;               &lt;p&gt;Col 1&lt;/p&gt;               &lt;p&gt;Text.&lt;/p&gt;           &lt;/div&gt;   &lt;/div&gt;   &lt;/span&gt;       &lt;/div&gt;     &lt;/div&gt;     &lt;div class="span4 widget-span widget-type-custom_widget"&gt;       &lt;div class="cell-wrapper layout-widget-wrapper"&gt;         &lt;span&gt;&lt;div class="clearfix cta-wrapper"&gt;         &lt;div class="cta-text"&gt;             &lt;p&gt;Col 2&lt;/p&gt; &lt;p&gt;Text.&lt;/p&gt;         &lt;/div&gt; &lt;/div&gt; &lt;/span&gt;&lt;/div&gt;     &lt;/div&gt;     &lt;div class="span4 widget-span widget-type-custom_widget"&gt;       &lt;div class="cell-wrapper layout-widget-wrapper"&gt;         &lt;span&gt;&lt;div class="clearfix cta-wrapper"&gt;         &lt;div class="cta-text"&gt;             &lt;p&gt;Col 3&lt;/p&gt;             &lt;p&gt;Text&lt;/p&gt;         &lt;/div&gt; &lt;/div&gt; &lt;/span&gt;&lt;/div&gt;     &lt;/div&gt;   &lt;/div&gt; &lt;/div&gt;     As you can see, the blue divs are more left aligned than being in the middle.
How can I horizontally center a &lt;div&gt; within another &lt;div&gt; using CSS? &lt;div id=&quot;outer&quot;&gt;   &lt;div id=&quot;inner&quot;&gt;Foo foo&lt;/div&gt; &lt;/div&gt;
tense and time and composite sentence If the eating meal starts at 7:00 AM and finishes at 8:00 AM. the drinking liquor starts at 7:00 AM and finishes at 7:50 AM.  can I say that :   I drank the liquor when I ate the meal. I ate the meal when I drank the liquor.   Is I need to use progressive tense ? I am non EU national, living in a Schengen country for past 5 years. I hold Indian passport and EU permanent residence card valid for 5 years.   Can i go to UK for few days to visit friends without a visa?  I am aware that UK is not in Schengen, and Schengen visas and residence permits issued by Schengen country is not valid for United Kingdom? But what about the PR card issued by a Schengen country?  I am also aware that EU citizens carrying EU passport have no restrictions to visit UK. Would you ever stop rolling the die? How to use measured step response to tune control system How does one use a measured step response to tune either a PID or convolution control scheme? Inspired by , I'm interested a more detailed explanation of how to implement a control system based on the measured step response.  I would not try to guess all the effects.  There are probably some non-obvious things going on, and you can't know all the parameters. I would measure the step response.  Find two pump settings that both result in the ball being within the measurable range within the tube.  Then have the controller suddenly switch from one setting to the other open loop.  Meanwhile measure what the ball does over time.  That is the step response.  You can take the derivative of that and get the impulse response.  From the impulse response you can predict the motion of the ball for any history of pump settings, assuming this is a linear system.  It is probably linear enough over the small range of settings to keep the ball within its normal range. You can use this as a simulation base to find the parameters for old fashioned PID control.  Or you can use the impulse response directly to do a convolution control.  You have to low pass filter the control input enough so that convolution kernel doesn't go negative unless your pump is actually reversible and can suck the ball back down.  How exactly does this work? ; I assume &quot;convolution control&quot; is the use of the pole-zero or transfer function, but don't see exactly how to get the parameters. RELATED:  * We are planning a trip with a bike rack attached to our trailer hitch. What is the best way to lock the bikes while the vehicle is unattended? I see some racks have locks on the knobs but they don't seem very strong.   What do you suggest? How do I identify the C terminal on my HVAC? How do I identify the C terminal on an HVAC, furnace, or boiler? If the terminals don't have a screw labeled C what should I look for on the wiring diagram? What steps should I take if a wiring diagram cannot be found or if it indicates that a C terminal doesn't exist?  Note: This is an extension to  which asks about running the wires through the wall. This question is about where to connect the wire at the HVAC. Can you create a strong blockcipher with small blocksize, given a strong blockcipher of conventional blocksize? Suppose I want a strong 20-bit blockcipher.  In other words, I want a function that takes a key (suppose the key is 128 bits), and implements a permutation from 20 bits to 20 bits.  The set of permutations should be close to a randomly-chosen subset of size $2^{128}$ of all $2^{20}!$ permutations on 20 bits.  I don't want you to build a new blockcipher from scratch.  Instead, assume you have a "strong" blockcipher like AES (128-bit blocksize, 128-bit keysize) and use this to build your 20-bit cipher.   Of course, your construction should be practical (i.e., you should be able to run it in both directions with reasonable amounts of time and memory). Where can the viewport clipping parameters be changed? The following is a rigorous proof of De Moivre's theorem by means of mathematical induction. The theorem put simply is that:  Any complex number, $z = a+bi$, on a cartesian plane can be expressed in polar form, where $a=r\cos\theta$ and $b=r\sin\theta$ and $r$ is the absolute distance from the origin to the point $z$. In light of this, the expression for the complex number $z$ in polar form is $z=r(\cos\theta+i\sin\theta)$ In order to find the $n^{th}$ power of $z$, the following rule applies: $$\displaystyle z^n=(r(\cos\theta+i\sin\theta))^n=r^n(\cos n\theta+i\sin n\theta)$$ where $n\in\mathbb N$ (I have confined $n$ to the natural numbers given that I intend on using mathematical induction to prove the theorem.  Base step: We must prove that what is stated is true for $n=1$, hence $$z^1=r^1(\cos 1\cdot\theta+i\sin1\cdot \theta)$$ $$=r(\cos\theta+i\sin\theta)$$ which is true. Next we assume it is true for $n=k$, and therefore proceed to the inductive step. Inductive step: When calculating $z^{n+1}$, it's the same as calculating $z^nz$, hence $$z^{n+1}=(r^n(\cos n\theta + i\sin n\theta))(r(\cos \theta+i\sin \theta))$$ $$=r^nr(\cos n\theta+i\sin n\theta)(\cos\theta +i\sin \theta)$$ $$=r^{n+1}(\cos n\theta\cdot\cos\theta+\cos n\theta \cdot i\sin\theta+i\sin n\theta\cdot\cos\theta+i^2\sin n\theta\cdot\sin\theta)$$ from here, $i^2=-1$, and therefore $+i^2\sin n\theta\cdot\sin\theta$ becomes $-\sin n\theta\cdot\sin\theta$. In addition to this, the following trigonometric identities will be used: $$\sin(n\theta + \theta) = \sin n\theta\cdot\cos\theta+\cos n\theta\cdot\sin\theta$$ $$or$$ $$k\sin(n \theta+\theta)=k\sin n \theta\cdot\cos \theta + \cos n\theta\cdot k\sin\theta$$ $$and$$ $$\cos(n \theta + \theta)=\cos n\theta\cdot\cos\theta-\sin n\theta\cdot\sin\theta$$ by using these, the original equation has now become $$=r^{n+1}(\cos(n \theta + \theta) + i\sin(n \theta + \theta))$$ then, after factoring out $\theta$, the theorem becomes $$=r^{n+1}(\cos((n+1)\theta)+i\sin((n+1)\theta))$$ which completes the proof. Question: is this proof correct all the way through? Or have I missed any conditions? If all is well in the case of this proof, could somebody aid me in proving it for $\{n|n\in\mathbb R,n\geq1\}$ How to prove that the only subgroup of the symmetric group $S_n$ of order $n!/2$ is $A_n$?  Why isn't there other possibility?  Thanks :) How to include graphics with spaces in their path? I want to import graphics into my main input file using the macro \includegraphics. It does not work if the filename contains spaces.   also discusses this subject, but there is no solution there.  My compilation routine is latex->dvips->ps2pdf (because of PSTricks). Why is this command not working: "ps aux | grep xscreensaver" I didn't see any hits about this on google, so I'm asking you:  I just tried to run this command in an ssh session, local is Debian Wheezy KDE, remote is Fedora 21 Gnome:  ps aux | grep xscreensaver   and this is the output:  bash:  grep: command not found...   I never seen this before, what is the cause?  I just few hours before updated the system, but didn't see any packages marked for removal. There are only two users on the system, and only me installs or removes software on it.  EDIT #1  Here is the commands and output copied,notice that the space is not there the second time:  [root@Hostname ~]# ps aux |  grep xscreensaver bash:  : command not found... [root@Hostname ~]# ps aux | grep xscreensaver bash:  grep: command not found... Is the sub-field of algebraic elements of a field extension of $K$ containing roots of polynomials over $K$ algebraically closed? Page title with substitution on views page I have a view page that requires a dynamic page title. It is a simple substitution of the label field.  If I use {{ label }} it works fine for the title displayed on the page, but it doesn't substitute the label for the actual page title (in meta)  I was able to fix this by using hook_views_post_render using the following code  // Set the route title. $route = \Drupal::routeMatch()-&gt;getCurrentRouteMatch()-&gt;getRouteObject(); $route-&gt;setDefault('_title', $title);  $view-&gt;setTitle($title);   However, the title only works if the page is not cached. For the cached pages, the page title is missing. This feels like a bug in drupal, but I am hoping that there is a simple way to get this done. Markov's paper on insolubility of the homeorphy problem What happens to the Windows 7 key when upgrading to Windows 8? Microsoft is offering "Microsoft Windows 8 Professional Upgrade" at a discounted price compared to the OEM version. However it states:     If you currently have a personal computer running Windows 7, Windows XP or Windows Vista then you can upgrade to Windows 8 Pro (Professional).   My question is what happens to the Windows 7 key that I use to upgrade? Will it become the Windows 8 key or will it generate a new Windows 8 key?  Basically if I upgrade using my Windows 7 key from my laptop for my desktop will I be able to continue using the laptop on Windows 7 while concurrently using Windows 8 upgrade on my Desktop? 9-speed system to 11-speed drivetrain upgrade? Factorisations of permutations Swing's KeyListener and multiple keys pressed at the same time Let $f: \Bbb C \to \Bbb C$ be an entire (analytic on the whole plane) function such that exists $\omega_1,\omega_2 \in \mathbb{S}^1$, linearly independent over $\Bbb R$ such that: $$f(z+\omega_1)=f(z)=f(z+\omega_2), \quad \forall\,z\in \Bbb C.$$Prove that $f$ is constant.   The intuition seems clear to me, we have the three vertices of a triangle given by $0$, $\omega_1$ and $\omega_2$. All points in the plane are one of the vertices of that triangle under a suitable parallel translation. The constant value will be $f(0)$, fine. Throwing values for $z$ there, I have found that $$f(n\omega_1) = f(\omega_1) = f(0)=f(\omega_2) = f(n\omega_2), \quad \forall\, n \in \Bbb Z.$$  I don't know how to improve the above for, say, rationals (at least). Some another ideas would be:   Checking that $f' \equiv 0$. I don't have a clue of how to do that. Write $w = a\omega_1+b\omega_2$, with $a,b \in \Bbb R$, do stuff and conclude that $f(w) = f(0)$. This approach doesn't seem good, because I only have a weak result with integers above. Finding that $f$ coincides with $f(0)$ on a set with an accumulation point. This seems also bad: the set on with $f$ coincides with $f(0)$ by which I found above is discrete.    Nothing works and this is getting annoying... And I don't see how analyticity comes in there. I'll be very thankful if someone can give me an idea.  (On a side note.. I know that this title is not informative at all. Feel free to edit if you come up with something better.)