I want to know how install and manage packages for TeX Live 2011 on Linux Open Suse; with Windows systems it is possible to manage packages for TeX Live with the Package Manager program included in the MiKTeX installation, but I don't now how to install and manage packages for TeX Live on Linux. I installed TeX Live 2011 with YaST2 Software Management but when I want execute the command tlmgr I get the following message:       dev@dhcppc1:~&gt; tlmgr If 'tlmgr' is not a typo you can use command-not-found to lookup the package that contains it, like this:     cnf tlmgr   So, how I can manage packages if tlmgr is not found or does not work? How I can "reinstall" tlmgr?  My TeX Live version is: TeX, Version 3.1415926 (TeX Live 2011) My OS:  Open Suse 12.2
I'm trying to compile a document that only works with an up-to-date distribution, so I'd like to know: how do I update my distribution? Please provide screenshots where appropriate.  List of answers           To keep an eye on what’s going on at CTAN you may subscribe to the  or the RSS feed feed://www.mail-archive.com/ctan-ann@dante.de/maillist.xml
In classical logic, why is $(p\Rightarrow q)$ True if $p$ is False and $q$ is True? Provided we have this truth table where "$p\implies q$" means "if $p$ then $q$":  $$\begin{array}{|c|c|c|} \hline p&amp;q&amp;p\implies q\\ \hline T&amp;T&amp;T\\ T&amp;F&amp;F\\ F&amp;T&amp;T\\ F&amp;F&amp;T\\\hline \end{array}$$  My understanding is that "$p\implies q$" means "when there is $p$, there is q". The second row in the truth table where $p$ is true and $q$ is false would then contradict "$p\implies q$" because there is no $q$ when $p$ is present.  Why then, does the third row of the truth table not contradict "$p\implies q$"? If $q$ is true when $p$ is false, then $p$ is not a condition of $q$.  I have not taken any logic class so please explain it in layman's terms.       Administrative note. You may experience being directed here even though your question was actually about line 4 of the truth table instead. In that case, see the companion question  And even if your original worry was about line 3, it might be useful to skim the other question anyway; many of the answers to either question attempt to explain both lines. MySQL 5.5.16 allows anonymous connections Apparently, I can connect to MySQL (at least from my localhost) without having to provide any username or password. I can even put anything as username, as long as the password is empty. I have access to the information_schema and test databases. I can create tables. If I run SELECT USER() it returns the proper value randomstring@localhost, where the random string is whatever I used for username when I connected.  The mysql.user table contains root@localhost, root@127.0.0.1, @localhost and pma@localhost. I manually set encrypted passwords to all the records (UPDATE user SET password=...) and only root has any privileges, the other two records have "N" for all privileges. That record with the empty username looks suspicious, but I don't think it has anything to do with this and I think it was there from the beginning.  To make matters worse, if I add a user with a password, I can only connect using empty string as password (just like if I put anything as username). If I try to connect using the username I created and password I supplied when creating it (CREATE USER .. IDENTIFIED BY ..) it doesn't work.  Does anyone know what is wrong and how I can fix this?  Note: I am using MySQL 5.5.16 for Windows, provided by the XAMPP package. Group of positive rationals under multiplication not isomorphic to group of rationals Why is the potential energy equal to the negative integral of a force? Why is the potential energy equals to the negative integral of a force? I am really confused with this negative sign. For example, why there is a negative sign in the gravitational potential energy and what does it mean?   I read that the negative sign means you do the same force but in the opposite direction.  Doesn't that mean the object shouldn't move? How to list the properties of a JavaScript object? Say I create an object thus:  var myObject =         {"ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*"};   What is the best way to retrieve a list of the property names? i.e. I would like to end up with some variable 'keys' such that:  keys == ["ircEvent", "method", "regex"] Remove all packages installed from a PPA? I have installed LibreOffice 4 using PPA. I was using LibreOffice 3, then  I had upgraded to LibreOffice 4, because I was somewhat eager to try a new version.   Now since I found that LibreOffice 4 has some issues, including handling my native language, I want to move back to LibreOffice 3.  This question  has already some answers which has some similarity with my above mentioned issue, but it does not solve my problem. This question talks about downgrading from a specific version of LibreOffice, namely from 4.0 to 3.6. The solutions mentioned are not the ones I am looking for. They will work, but the  solutions suggest either downloading .deb files for LibreOffice 3.6 or adding PPA for them. Furthermore, some of the answers put out-of-proportion~(applicable for the solution, however) stress on use of , not general command-line-solution.     I want a general solution without using PPA or downloading .deb files. All I want is to move back from the (higher) PPA version to the (lower) official version.  Anyway, in order to accomplish this, I removed the LibreOffice config directory from my home and then purged LibreOffice from my machine.  sudo apt-get purge libreoffice-*   Then I removed the relevant PPA's using the sudo apt-add-repository --remove command. And then ran sudo apt-get update.  Now, when I try to install LibreOffice using the command  sudo apt-get install libreoffice   I get an avalanche of output about unmet dependencies, something like,   The following packages have unmet dependencies:  libreoffice : Depends: libreoffice-core (= 1:3.5.7-0ubuntu4) but it is not going to be installed (snipped)    If I dig the issue further, by using the command,  sudo apt-get install libreoffice-core   I get    The following packages have unmet dependencies:  libreoffice-core : Depends: libreoffice-common (&gt; 1:3.5.7) but it is not going to be installed                 Depends: libexttextcat0 (&gt;= 2.2-8) but it is not going to be installed                 Depends: ure (&gt;= 3.5.7~) but it is not going to be installed E: Unable to correct problems, you have held broken packages.    Could you please tell me how do I install LibreOffice 3 in my machine?  I am using Ubuntu 12.04 LTS.    EDIT  Before receiving , I was wondering, at this very moment, if I take a fresh computer, and install Ubuntu 12.04, LibreOffice installation will work without a hitch. Then why I can not install LibreOffice in my 12.04 machine today from simple command line?  Then the accepted answer clarified everything. I need to use ppa-purge so that this resets all packages from a PPA to the standard versions released for my distribution.  Basically it is like a way to restore my system back to the way it was before my installed packages from a PPA.  further elaborates the idea.    worked perfectly for me. Actually, this was an education for me since it taught me how do downgrade a package that was added via PPA. And I realized that the answer actually teaches us to "move from PPA installation  of a package to official lower version package." I've seen many science popularisation documentaries and read few books (obviously not being scientist myself). I am able to process and understand basic ideas behind most of these. However for general relativity there is this one illustration, which is being used over and over (image from Wikipedia):    I always thought that general relativity gives another way how you can describe gravity. However for this illustration to work, there needs to be another force, pulling the object down (referring to a direction in the attached image). If I put two non-moving objects in the image, what force will pull them together?  So where is my understanding incorrect? Or is general relativity not about explaining gravity and just describes how heavy objects bends spacetime (in that case the analogy is being used not correctly in my opinion)?    UPDATE Thank you for the answers and comments. Namely the XKCD comics is a spot on. I understand that the analogy with bent sheet of fabric pretty bad, but it seems that it can be fixed if you don't bent the fabric, but just distort the drawn grid.   Would you be so kind and answer the second part of the question as well - whether general relativity is explaining gravitational force. To me it seems that it is not (bending of spacetime simply can not affect two non-moving objects). However most of the time it is being presented that it does. I've always heard this reasoning, and it makes obvious sense, but how do you actually show it for some arbitrary product? Would it be something like this?  $$(a(b(cd)))e=((ab)(cd))e=(((ab)c)d)e=abcde?$$  Do you just say that the grouping of the parentheses now corresponds to just multiplying straight through? Thanks. Usage and origin of "sister" in expressions like "sister company, sister ship, sister site" etc The term  is often  used figuratively  to refer, for instance,  to a “sister company” for a company  within the same group, or to a “sister  site” for  sites that belong to the same family. This connotation as explained by the   means:         belonging to a pair or group of similar and related things, such as businesses, usually owned or operated by the same person or organization:         our sister company in Australia.          also, from :        You can use sister to describe something that is of the same type or is connected in some way to another thing you have mentioned.    ⇒ ...the International Monetary Fund and its sister organisation, the World Bank.   ⇒ ...Voyager 2 and its sister ship, Voyager 1.       This usage appears to be common with things that are  regarded as feminine and are associated, as if by kinship,  with other similar things that belong to the same group. An early  usage example of this is the "sister" referred to  ships:         the US battleship Missouri and her sister ship, the Wisconsin.      In other instances,  the "feminine" issue is less explicit as in the case of internet sites, so I guess this usage has to do with the fact that English is less gender specific when it comes to things or abstract entities.   Questions:    Does “sister” apply to whatever entity that belongs to the same group irrespective of its real or perceived gender? or could "brother" be used instead?  Where does this usage come from? How do I get the difference between two Dates in JavaScript? I'm creating an application which lets you define events with a time frame.  I want to automatically fill in the end date when the user selects or changes the start date.  I can't quite figure out, however, how to get the difference between the two times, and then how to create a new end Date using that difference. Bottom frame of listing appears on top of the next page Why are 50mm Lenses Cheaper? How do you iterate backwards through an STL list? How to differentiate a given inner product (CSIR DEC(2018) Let $A$ be a $n \times n$  invertible  matrix.Define a function $F:\mathbb{R}^{n} \times \mathbb{R}^{n} \rightarrow \mathbb{R}$ by $F(x,y)=\langle Ax,y\rangle$. Let $DF(x,y)$ denotes the derivative of $F$ at $(x,y)$ which is a linear transformation from $\mathbb{R}^{n} \times \mathbb{R}^{n} \rightarrow \mathbb{R} $. Then      1) if $x\neq 0$,then  $DF(x,0)\neq 0$      2) if $y\neq 0$,then  $DF(0,y)\neq 0$      3)  if $(x,y)\neq (0,0)$,then $DF(x,y)\neq 0$      4) if $x=0 \; or \;y=0$,then $DF(x,y)= 0$   I don't even know how to start the solution and also how to take derivative in higher dimensions.  Please help!  Thank you. I need help to calculate the  Fourier transform of this funcion  $$b(x) =\frac{1}{x^2 +a^2}\,,\qquad a &gt; 0$$ Thanks. I recently received an old iMac secondhand.  I have no way to reach the original owner. I am trying to upgrade the OS software, but the prompts demand the administrator's name (which is auto-filled) and password (which I do not have).  I understand why these security features are in place, but is there any way in the world for me to access Admin. privileges without the password? What is the difference between an indeterminate and variable? From Wikipedia-     In mathematics, and particularly in formal algebra, an indeterminate is a symbol that is treated as a variable, but does not stand for anything else but itself and is used as a placeholder in objects such as polynomials and formal power series.   So, how it is different from variable which is also used as a placeholder? What is the use of the indeterminate? Best lens for taking pictures of surfers I'm just trying to decide which new lens to get. I need to take surf and windsurf photos from onshore. Sometimes 300 mm is enough but there are many times they are too far away. I have a sigma 70-300 but I need something better, if the light is not perfect it doesn't give me the sharpness I hope for. I can not afford the 400L 2.8 of course, so I'm trying to choose between the Canon EF 100-400L, Canon EF 70-300L (which I heard is far better than the base one), or Sigma 50-500. My body is a canon 600D. Is there a proof from the first principle that for the Lagrangian $L$,    $$L = T\text{(kinetic energy)} - V\text{(potential energy)}$$  in classical mechanics? Assume that Cartesian coordinates are used. Among the combinations, $L = T - nV$, only $n=1$ works. Is there a fundamental reason for it?  On the other hand, the variational principle used in deriving the equations of motion, Euler-Lagrange equation, is general enough (can be used to to find the optimum of any parametrized integral) and does not specify the form of Lagrangian. I appreciate for anyone who gives the  answer, and if possible, the primary source (who published the answer first in the literature).      Notes added on Sept 22: - Both answers are correct as far as I can find. Both answerers were not sure about what I meant by the term I used: 'first principle'. I like to elaborate what I was thinking, not meant to be condescending or anything near to that. Please have a little understanding if the words I use are not well-thought of. - We do science by collecting facts, forming empirical laws, building a theory which generalizes the laws, then we go back to the lab and find if the generalization part can stand up to the verification. Newton's laws are close to the end of empirical laws, meaning that they are easily verified in the lab. These laws are not limited to gravity, but are used mostly under the condition of gravity. When we generalize and express them in Lagrangian or Hamiltonian, they can be used where Newton's laws cannot, for example, on electromagnetism, or any other forces unknown to us. Lagrangian or Hamiltonian and the derived equations of motion are generalizations and more on the theory side, relatively speaking; at least those are a little more theoretical than Newton's laws. We still go to lab to verify these generalizations, but it's somewhat harder to do so, like we have to use Large Hadron Collider. - But here is a new problem, as @Jerry Schirmer pointed out in his comment and I agreed. Lagrangian is great tool if we know its expression. If we don't, then we are at lost. Lagrangian is almost as useless as Newton's laws for a new mysterious force. It's almost as useless but not quite, because we can try and error. We have much better luck to try and error on Lagrangian than on equations of motion. - Oh, variational principle is a 'first principle' in my mind and is used to derive Euler-Lagrange equation. But variational principle does not give a clue about the explicit expression of Lagrangian. This is the point I'm driving at. This is why I'm looking for help, say, in Physics SE. If someone knew the reason why n=1 in L=T-nV, then we could use this reasoning to find out about a mysterious force. It looks like that someone is in the future. Pause button started working for Chrome / Youtube, messing with audio player controls