View source for User talk:Ulf Rehmann

== Another spammer ==

Please notify me about spammers by dropping a note here with a link to
their home page like this:

[[User:KennywSilverstone]]

Wouldn't it be better to ''delete'' spam accounts (after checking their contributions) instead of only blocking them? Blocked-only spammers still "spam" the user list. --[[User:Peter Schmitt|Peter Schmitt]] 13:36, 27 January 2012 (CET)

:Deleting spam accounts would be good, but there is no tool to delete a user here, see [[Special:ListGroupRights | this]]. Just "pages" can be deleted. There is this [http://www.mediawiki.org/wiki/Extension:User_Merge_and_Delete Extension], I can propose to the sysadmins to install this extension (I myself can't do that).  However, today they announced to me they will install a "Double-opt-in" registration process in order to defeat spammers. --[[User:Ulf Rehmann|Ulf Rehmann]] 15:35, 27 January 2012 (CET)
 
:: Even if spammers are kept out in the future this extension would be useful to clean up the past. --[[User:Peter Schmitt|Peter Schmitt]] 00:33, 29 January 2012 (CET)

== Could we also have such a meeting place? ==

Something similar to [http://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Mathematics this] would be useful. (Or like [http://knowino.org/wiki/Knowino:Village_Inn this]. But please, not like [http://forum.citizendium.org/ this].) And by the way, did you see [http://en.wikipedia.org/wiki/Wikipedia_talk:WikiProject_Mathematics#Encyclopaedia_of_Mathematics this topic]? An EoM-relevant quote from there follows. --[[User:Boris Tsirelson|Boris Tsirelson]] 15:05, 13 December 2011 (CET)

:"I am the product manager at Springer responsible for managing the technical implementation of the new EOM wiki. I have adapted the citation template documentation for the template:SpringerEOM to use the proper naming convention for the new site. I will be closely watching the site's incoming traffic from WP and updating the ids of WP citations that used the template so that their link-outs will resolve to not only the correct article in the new EOM wiki, but to the version of the article that is identical to the version previously hosted at eom.springer.de.--Nbrothers (talk) 16:13, 30 November 2011 (UTC)"

== Categories ==

Something is wrong, I guess; we have now both [[:Category:Dynamical Systems and Ordinary Differential Equation]] and [[:Category:Dynamical Systems and Ordinary Differential Equations]]. :-)
:Thanks. I guess I fixed this.--[[User:Rehmann|Ulf Rehmann]] 22:43, 9 January 2012 (CET)
And by the way: when all first chars are uppercase and when they are not? --[[User:Boris Tsirelson|Boris Tsirelson]] 22:23, 9 January 2012 (CET)
:Aha, I was careless here. What is the Wikipedia convention? What happens if I rename a category? Will the renameing shift all the entries in its files?--[[User:Rehmann|Ulf Rehmann]] 22:43, 9 January 2012 (CET)
::On WP they are generally lowercase; [http://en.wikipedia.org/wiki/Category:Probability_theory example]. No, I am afraid changes in all pages need to be made by hand. And by the way, also replacement of "unofficial" templates to "official" ones (when ready) will be made by hand. Unless we'll create corresponding [http://en.wikipedia.org/wiki/Wikipedia:Bot bots], which is feasible but not so easy (as any programming). --[[User:Boris Tsirelson|Boris Tsirelson]] 22:47, 9 January 2012 (CET)
:::Ok. I'l fix the cases issues. Concerning the templates we'll see later. I guess when programming bots one needs admin access to the machine where the wikimedia is installed? That I don't have (otherwise we'd already have the ParserFunctions ext.... --[[User:Rehmann|Ulf Rehmann]] 23:32, 9 January 2012 (CET)
::::You mean, the root access. No. Not even admin rights on the wiki. I did it once on Wikipedia, being just a plain user. --[[User:Boris Tsirelson|Boris Tsirelson]] 06:47, 10 January 2012 (CET)
::::: But for organizational reasons bots are best run from separate "bot" accounts. [http://meta.wikimedia.org/wiki/Bot This] link may be helpful. --[[User:Peter Schmitt|Peter Schmitt]] 15:16, 10 January 2012 (CET)
::::::Thanks for your hints. I did find [http://search.cpan.org/~lifeguard/MediaWiki-Bot-v3.4.2/lib/MediaWiki/Bot.pm perl based bot] which works.--[[User:Rehmann|Ulf Rehmann]] 12:25, 11 January 2012 (CET)

== Keeping spammers away ==

It could help, to provide an account only after asking a math question and getting the right answer. The question should be replaced from time to time. Here is one, for example. :-)

Calculate the area of the set of points $(x,y)\in\R^2$ satisfying
\[
\Big( \frac{x-5}{\sqrt{15}-2} \Big)^2 + \Big( \frac{y+3}{\sqrt{15}+2} \Big)^2 \le \frac3\pi \, .
\]
--[[User:Boris Tsirelson|Boris Tsirelson]] 11:12, 14 January 2012 (CET)

And we should not underestimate the problem. See e.g. [http://en.wikipedia.org/wiki/Spambot#Forum_spambots], [http://en.wikipedia.org/wiki/XRumer]. --[[User:Boris Tsirelson|Boris Tsirelson]] 13:27, 14 January 2012 (CET)

:Something like the above has been implemented. Look at [[Special:Version]], search for  "ConfirmEdit". Questions are less sophisticated though. --[[User:Ulf Rehmann|Ulf Rehmann]] 13:35, 1 February 2012 (CET)

::Well, I am glad it is considered seriously. But now (a) it asks me a question whenever I edit something, and (b) a bot can solve such questions easily. I'd prefer not to bother users that have accounts, but to ask harder questions when creating accounts. Like [http://www.mediawiki.org/wiki/Extension:QuestyCaptcha QuestyCaptcha]. Of course, it is reasonable to reconsider accounts that exist when such system starts. --[[User:Boris Tsirelson|Boris Tsirelson]] 20:51, 3 February 2012 (CET)
::: I agree with your suggestions: it is inconvenient to  have to answer a question every time one does a tiny edit. (In fact I was not aware of this fact until now.) I will mention this to the sysadmins and propose to modify this. However, all these things apparently need time. --[[User:Ulf Rehmann|Ulf Rehmann]] 21:24, 3 February 2012 (CET)

Unfortunately, my [[User talk:EddieBates|prediction]] seems to come true: "Typical solutions tend to be broken by newer spambots". --[[User:Boris Tsirelson|Boris Tsirelson]] 10:38, 28 March 2012 (CEST)

== Obsolete pages ==

Please delete (include pages here for deletion):

* [[User:Boris Tsirelson/Anchor]]

== Suggested move ==

I suggest to move [[Surjection]] to [[surjective function]] (leaving a redirect). 
I think that the adjective is more often used than the noun.
(Move is listed among the "user" rights, but there is no "move" button.)
--[[User:Peter Schmitt|Peter Schmitt]] 02:47, 14 February 2012 (CET)

:I have a "move" button, thus I guess you have, too. But maybe it does not fit into the (not so wide) window. Maybe after "Read", "Edit" and "View history" you have a small black triangle; put the cursor on it, and hopefully you get "Move" and "Watch". --[[User:Boris Tsirelson|Boris Tsirelson]] 07:13, 14 February 2012 (CET)
:: (Blushing) I overlooked this. In fact, now I remember that I noticed it some time ago but did not think of it now ... --[[User:Peter Schmitt|Peter Schmitt]] 17:36, 14 February 2012 (CET)

I propose not to move "surjection" to "surjective function", as there are the notions of "surjective mapping" or "surjective morphism" etc. as well, which are all covered by the notion "surjection". You may want to look into MathSciNet for occurences of "surjection" under "anywhere" or even under "title" to find that notion used quite commonly. --[[User:Ulf Rehmann|Ulf Rehmann]] 09:44, 14 February 2012 (CET)
: On the contrary, I'd say. In my view, these related concepts are an argument for having pages for each of them and using "surjection" or/and "surjective" as disambiguation pages pointing to them. (By the way, I think that [[function]] and [[mapping]] need to be better "coordinated". What do you think?) --[[User:Peter Schmitt|Peter Schmitt]] 17:36, 14 February 2012 (CET)

::Oh, well, is there any need to split some page of almost empty content (about surjection) into several disambiguated pages? On the other hand, your suggestion to coordinate the pages [[function]], [[mapping]] definitely makes sense. But there are much more pages involved, at least [[Multi-valued mapping]], [[Correspondence]] (here the notion within algebraic geometry certainly has to be expanded into a complete section, if not into a page of its own), further: [[Permutation]], [[Morphism]], [[Isomorphism]], [[Epimorphism]], [[Monomorphism]], [[Endomorphism]] and the like (at the end of [[Morphism]] there are more), and then you are in the endless [[Category| realm of categories]], which gives you even more. --[[User:Ulf Rehmann|Ulf Rehmann]] 18:36, 14 February 2012 (CET)

:: {{Anchor|iso}} I have just operated the page [[Isomorphism]]. See there for Categorization and literature, which is may be of relevance for the item [[Bijection]]. Mutual links probably were nice. --[[User:Ulf Rehmann|Ulf Rehmann]] 14:54, 18 February 2012 (CET)

== Mistake needs correction ==

By mistake I moved [[Helly number]] instead of [[Helly theorem]] to [[Helly's theorem]].
I could revert the move, but now the redirect has to be deleted. Sorry for that! --[[User:Peter Schmitt|Peter Schmitt]] 23:53, 6 March 2012 (CET)
: Done. --[[User:Ulf Rehmann|Ulf Rehmann]] 00:13, 7 March 2012 (CET)
:: Thanks. --[[User:Peter Schmitt|Peter Schmitt]] 00:38, 7 March 2012 (CET)

== Page ready for checking ==

Hi Ulf -- the page [[User:Ulf Rehmann/PreTeX:Banach algebra]] is TeXed and ready for moving (I could not move it myself -- "page exists").  Cheers, Jim

Hi Ulf -- the Banach space page is TeXed, I moved it to [[Banach space PostTex]].  There are a few notes in the discussion page too.  Could you please move this to [[Banach space]], Cheers, Jim --[[User:Jjg|Jjg]] 01:32, 19 April 2012 (CEST)
: Is there any way for a normal user to do this (to move one page onto another) without harassing you all the time? --[[User:Jjg|Jjg]] 21:59, 19 April 2012 (CEST)

== Pretex request ==

Hi Ulf -- I find myself with a bit more time to contribute.  Could you do the same "PreTeX"ing for me for [[Topological algebra]], [[Banach space]], [[Commutative Banach algebra]], [[C*-algebra]], [[Group algebra]].  I see that this is done by an emacs script, but unfortunately I've not been able to get "its just text" to work on my version of firefox. (if there is another way please let me know/point me to the relevant page). --[[User:Jjg|Jjg]] 15:52, 16 April 2012 (CEST)
: Hi Sergei, it seems you did use a wrong signature: The name of your user page is [[User:Yakovenko]], not what is shown in your signature. But the way, in case you want to change that name, I could do that for you.
: Concerning "It's all text": In case you use emacs: You have to give the emacs command "M-x server-start" before clicking on the little edit button in oder to get it to work. I personally don't use firefox, but rather chromium, for which a similar macro has to be applied. The emacs script is very helpful, because allows to use the emacs minibuffer to reedit code which had been keyed in a bit before (just by using the up/down arrows).
: Concerning PreTex: Will do so. I'll put the stuff into the respective discussion page of either page, with a short preamble or so. In fact we could do this for every page, since this can be automated. (However, I think the method above allows to work much faster...) --[[User:Ulf Rehmann|Ulf Rehmann]] 17:31, 16 April 2012 (CEST)

: Hi Ulf -- Actually the sig is right: I am "J.J. Green"!.  Thanks for the emacs advice, but in fact the problem seems to be my version of firefox conflicting with addon (there is no "edit button"), I'll try chrome ... Cheers --[[User:Jjg|Jjg]] 17:41, 16 April 2012 (CEST)

:: Ok, sorry, I realized too late I was talking to the wrong addressee... Seems I'm talking to too many at the same time. Maybe you put some id into your user page?
:: The toy for chrome is "Edit with Emacs": https://chrome.google.com/webstore/detail/ljobjlafonikaiipfkggjbhkghgicgoh
:: You should configure your emacs so that it honors utf-8, and also, that you don't close or leave chrome's edit window while you are editing in emacs, since this would mean you loose contact with the server, and if you close your emacs buffer than its content may be lost. 
:: Another thing: I have, in my .emacs file, a line
:: <nowiki>(add-hook 'edit-server-start-hook 'turn-off-auto-fill)</nowiki>
:: because otherwise emacs tends to autofill the whole buffer, thereby destroying WP links. For convenient editing you can use M-x longlines-mode. --[[User:Ulf Rehmann|Ulf Rehmann]] 18:20, 16 April 2012 (CEST)
::: Hi Jim, I have prepared the pretex of the pages you mentioned in their respective talk pages. The [[Topological algebra]] had so little tex that I finished that rightaway (except that some MR/ZBL entries are too many, cold you please check and remove the nnosense?).
::: One more hint: The tex code entries in the above pretex files look like this <nowiki>"$ $"</nowiki>. This is good for direct editing. The emacs macro won't work well for that. If you want to use that, you should make a global replacement <nowiki>'$ $' ==> '$_$'</nowiki> first. Then you can apply the macro, and it will traverse you trough all the tex places. --[[User:Ulf Rehmann|Ulf Rehmann]] 20:07, 16 April 2012 (CEST)

== Help on sandbox ==

Do our help pages mention the idea of a (private) sandbox? This would be helpful, see for instance [[Talk:Normal form]] and [[User:Yakovenko/sandbox1]]. --[[User:Boris Tsirelson|Boris Tsirelson]] 07:43, 20 April 2012 (CEST)
:I was absolutely thrilled by the simplicity and elegance of this solution! ;-) As a novice to Wiki, I also would suggest one-line help on how to create new pages and rename the old ones (with appropriate caveats about redirection). [[User:Yakovenko|Sergei Yakovenko]] 12:44, 20 April 2012 (CEST)

== Help on equation numbering ==

This also would be helpful; see [[Talk:EoM:This project#Hadamard theorem]]. --[[User:Boris Tsirelson|Boris Tsirelson]] 16:25, 21 April 2012 (CEST)

== Pages that need some improvement ==

Hi Ulf. Is there a way to mark a page that needs to be updated or improved (or even created)? Or maybe to add it to a list somewhere? I've been doing some TeX conversion on two pages, and they both need a lot more than simple TeX conversion. They need to be updated and improved. Unfortunately, I have no time to do this right away, but maybe other people have. --[[User:Baptiste Calmes|Baptiste Calmes]] 22:41, 23 April 2012 (CEST)