How to know name of source branch in Git
How to find the nearest parent of a Git branch?
One of my favorite quotes is by Alvin Toffler which says:     The illiterate of the 21st century will not be those who cannot read   and write, but those who cannot learn, unlearn, and relearn.   The way I understand "relearn" in the quote is to learn something new that is different from what was originally learned.  I'm wondering in general if "relearn" convey learning the same thing again, or a different thing, or it depends on the context of the sentence. Is the same thing true for "learn again"? Is it possible to choose which OS will be loaded using a hardware switch? The annihilator of a module is an ideal Let $R$ be a ring and let $M$ be an $R$-module. Define the annihilator of $M$ to be the following subset of $R$:  $Ann_R(M) =\{r\in R \mid rm = 0_M  \text{ for all } m\in M \}$  Prove that $Ann_R(M)$ is an ideal of $R$.  please help as much as you can a full answer is greatly appreciated   Thanks Is the null set a subset of every set? Ever since day one of of my Mathematical Logic course, this fact has really bothered me. I cannot wrap my head around how an empty set is a subset of every possible set. Could someone kindly explain how this is true? Any help is appreciated! I'm having some troubles understanding the solution (going from step $2$ to step $3$) of this linear congruence equation. Here's the problem with the solution:   Solve the congruence $2x + 11 \equiv 7 \pmod 3$.   First, we reduce all the coefficients $\pmod 3$:  $$2x + 2 \equiv 1 \pmod 3. \tag{1}$$  Next, we add $1$ to both sides, using the fact that $2 + 1 \equiv 0 \pmod 3$:  $$2x \equiv 2 \pmod 3. \tag{2}$$  Finally, we multiply both sides by $2$, using the fact that $2 · 2 = 4 \equiv 1 \pmod 3$:  $$x \equiv 1 \pmod 3. \tag{3}$$  That is, any number in the set $\{\ldots, −5, −2, 1, 4, \ldots\}$ will solve the original congruence.    Like I said my problem is the step between $(2)$ and $(3)$. If I multiply both sides of $(2)$ by $2$ I get:  $$4x \equiv 4 \pmod 3.$$  Now, I understand that $4$ is congruent to $1 \pmod 3$ so the RHS "simplifies" to $1 \pmod 3$ but I don't understand why the LHS "simplifies" to $x$. Can someone help me with this? How to close/open a view panel I can't find a way to close a view panel, in particular the horizontal at the bottom, is pretty useless to me at this moment. Choosing OpenLayers or Leaflet? I was debating with one of my collegues on OpenLayers v/s Leaflet. I made a point that OpenLayers is much better API if we wish to build a project, where you need direct connectivity to the Geoserver and PostGIS.  Then I found , which looks pretty new but has the features of connectivity with the Geoserver and PostGIS.  So my project details are as follows,   Use the map interface to fetch Feature Info Create a customized tool that takes the lat/lon from user as to where he/she clicks on the map and then fetches the Climate Data from the raster (which is handled by a py script on the server) Allows user to upload excel, which is sent to the py script, which returns a GeoJSON, which creates Vector Features on the map Allow user to create vector polygons, which will fetch the Features it intersects from the WFS Layer. Fetches Layer from the PostGIS Datastore on GeoServer and displays the layers on the map.   So now I am confused on which is better and why using OpenLayers over Leaflet makes more sense or not? Different batteries connected in parallel If we have 2 batteries one of emf x and the other is of emf y and we connect them in series we get an effective emf of x+y.  But what if we connect them in parallel, how to calculate the emf now? How to unlock device when I forgot my password? I've read  which states that there is an option to disable the lock using my Google account information. However I did not noticed such an option when I entered my password five times wrong. (Although there was also a 20s or 30s delay to complicate brute force attacks.) I use Android 4.0.3 on a Asus Transformer Prime TF201.  Would factory reset work? I installed Ubuntu 12.04 a month ago and am using it till now. I failed to notice that all this time there was no sound at all while running Ubuntu, even while playing a game in Wine. The weird thing is that only the startup sound comes when I log in (Indian/African drum tone), then comes the utter silence.  I tested both Digital Output (S/PDIF) and the speakers in the sound settings but can hear nothing.  Any help? IIS7 - The request filtering module is configured to deny a request that exceeds the request content length Bypass GeneratedValue in Hibernate (merge data not in db?) Emoji Characters I'm trying to display Emoji Characters inside my XeLaTeX Document. It seems to work for some glyphs like the numbers and pound sign but not for all. Here is a MWE:  \documentclass{scrartcl}  \usepackage{fontspec}  \setmainfont{Apple Color Emoji} % The emoji Font   \begin{document} \char"0030{}  %Works \char"1F60D{} % Doesent Work should out put SMILEY FACE WITH HEART SHAPED EYES \end{document}   What is the reason for this strange behavior and is there a way to include Emojis in XeLaTeX?  Edit:   It seems the Character is there. It is selectable but not visible. I can copy&amp;paste it. Multivariate linear regression vs. several univariate regression models In the univariate regression settings, we try to model   $$y = X\beta +noise$$  where $y \in \mathbb{R}^n$ a vector of $n$ observations and $X \in \mathbb{R}^{n \times m}$ the design matrix with $m$ predictors. The solution is $\beta_0 = (X^TX)^{-1}Xy$.  In the multivariate regression settings, we try to model   $$Y = X\beta +noise$$  where $y \in \mathbb{R}^{n \times p}$ is a matrix of $n$ observations and $p$ different latent variables. The solution is $\beta_0 = (X^TX)^{-1}XY$.  My question is how is that different than performing $p$ different univariate linear regression? I read  that in the latter case we take into consideration correlation between the dependent variables, but I don't see it from the math. Applications losing focus for a few seconds in Windows 7 Recently all of my applications keep losing focus every minute (or so) for a few seconds (then the window gets the focus back). It is very annoying, since I'm typing most of the time and get interrupted by this behavior. Things worked fine until a week ago and I have no idea what is causing this error, but I noticed the mouse moves to a certain point on one of my screens when this happens.  I would appreciate any advice: it starts to drive me crazy... How can one have a mini table of contents for the current chapter appear just after the chapter name listing all sections of that chapter? What diceless tabletop RPG techniques are there? I am interested in using a diceless resolution system for my roleplaying, but am not sure what my options are in that vein. I can think of basically two categories of diceless tabletop role-playing systems - systems which eschew any randomisation, and those which randomise by some method other than dice.  Examples  Non-random tabletop systems  One option is of direct comparison of stats or other game statistics without a randomization factor. The obvious example here is Amber DRPG, but I suspect that there are other narrative driven RPGs out there that I don't know about.   Even in Amber, situation resolution it is rarely by direct comparison between stats. Narrative techniques can be used to manoeuvre two characters into a situation which narrows the gap between their ranking, widens it, or brings other stats into the picture - the classic example of course being Corwin relying on his stamina to stretch out conflicts with his siblings such that it becomes a dominant enough factor that he can escape.  Other randomisation techniques  I have seen card-based randomization system. Over the years, I've played quite a few home brew games based on the original SAGA Dragonlance system, which was similar to the SAGA Marvel superhero system.  The basic mechanics were that you had a hand size according to your experience, and for any skill check you would play a card from your hand and replace your card from the draw pile. If you had a card of the right suit as the skill check (a strength card on a strength check) you would also draw a card from the draw pile and add that to your skill check, so a small trump was often worth more than a medium value card not of the correct suit. When you were wounded, you would discard cards to the value of the damage, but those cards wouldn't be replenished - your hand size would be reduced until you were healed. One nice aspect of the system was that it simulated fatigue beautifully, you might start a scene with a spread of high, medium and low cards, but as your high cards were played they would more often than not get replaced by lower value cards, until you were left with a bunch of useless cards and feeling very vulnerable.    The only other system I've played without dice was Everway which, if I remember correctly, used a combination of these techniques, stats based resolution, card resolution and GM fiat.  What I would be interested in is what other diceless resolution techniques exist, ideally with examples of tabletop diceless resolution methods people have tried and how they found them to play. How to prove that $\lim_{n\rightarrow \infty}\frac {n^{2}}{2^{n}}=0$ & $\lim_{n\rightarrow \infty}\frac {n^{2}}{n!}=0$? Prove that:  $$\lim_{n\rightarrow \infty}\dfrac {n^{2}}{2^{n}}=0$$  I think I need to show $2^n \geq n^3$ $\forall n \geq10$. Is it true?  What about: $$\lim_{n\rightarrow \infty}\dfrac {n^{2}}{n!}=0$$  What to do with $n!$? $\forall a,b,c \in \mathbb{N}\!:\ a\mid b \Rightarrow ac\mid bc. $ Divisibility Proof Could someone verify this proof?  Given the following definition of divisibility $(\forall{a,b \in \mathbb{N}})[a \mid b \equiv (\exists{c \in \mathbb{N}})(ac=b)]$.  Statement: $(\forall{a,b,c \in \mathbb{N}})[(a\mid b) \rightarrow (ac\mid bc)] $ .  Proof:  Let $a,b \in \mathbb{N}$ be arbitrary.  Assuming that $a\mid b$, we can conclude that $\exists{d \in \mathbb{N}}$ such that $ad = b$.  By Algebra we can deduce the following sequence of statements.  If $(ad)=b$, then $(ad)c=bc$.  Therefore $(ac)d=bc$.  Hence by the definition of divisibility we know that $ac\mid bc$. How to set a shortcut for "Always on Top" for window? In 12.04 (Unity), I would like to assign a shortcut to the "always on top option" for a window. Probably something like Ctrl+Shift+Home to turn on and Ctrl+Shift+End to turn off, or whatever. Is there an option to do this somewhere in the Compiz Settings Manager?  This (old)  claimed that      For compiz, Enable Extra WM Actions. Check the properties, and insert ALT+A to Key field for Toggle Always-On-Top action.   But I couldn't find that.