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:

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. --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 this. Just "pages" can be deleted. There is this 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. --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. --Peter Schmitt 00:33, 29 January 2012 (CET)

Could we also have such a meeting place?

Something similar to this would be useful. (Or like this. But please, not like this.) And by the way, did you see this topic? An EoM-relevant quote from there follows. --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.--Ulf Rehmann 22:43, 9 January 2012 (CET)

And by the way: when all first chars are uppercase and when they are not? --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?--Ulf Rehmann 22:43, 9 January 2012 (CET)

On WP they are generally lowercase; 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 bots, which is feasible but not so easy (as any programming). --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.... --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. --Boris Tsirelson 06:47, 10 January 2012 (CET)

But for organizational reasons bots are best run from separate "bot" accounts. This link may be helpful. --Peter Schmitt 15:16, 10 January 2012 (CET)

Thanks for your hints. I did find perl based bot which works.--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 \[ \Big( \frac{x-5}{\sqrt{15}-2} \Big)^2 + \Big( \frac{y+3}{\sqrt{15}+2} \Big)^2 \le \frac3\pi \, . \] --Boris Tsirelson 11:12, 14 January 2012 (CET)

And we should not underestimate the problem. See e.g. [1], [2]. --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. --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 QuestyCaptcha. Of course, it is reasonable to reconsider accounts that exist when such system starts. --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. --Ulf Rehmann 21:24, 3 February 2012 (CET)

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.) --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". --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 ... --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. --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?) --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 realm of categories, which gives you even more. --Ulf Rehmann 18:36, 14 February 2012 (CET)