Talk:Marriage theorem
From Wikipedia, the free encyclopedia
 |
|||||||||||||||||||||||
| Mathematics rating: | Start Class | Mid Priority | Field: Discrete mathematics | ||||||||||||||||||||
|
|||||||||||||||||||||||
Is S allowed to be infinite? If so, this should probably be mentioned, and the link to cardinal number provided. AxelBoldt 21:01 Mar 2, 2003 (UTC)
- Saying S is "(not necessarily countable)" implies that it may or may not be infinite (since all finite sets are countable). But I don't see any reason to include a link to cardinal number. According to the text, S may have cardinality of any cardinal number (including finite ones). It may also be of size of any ordinal. Should we include references to ordinal numbers too? S is just a set. To say that should be enough--we shouldn't have to say what properties the set could have. Rob 20:09, 5 December 2005 (UTC)
It appears that the paragraph
- This can also be applied to the problem of Assignment: Given a set of n employees, fill out a list of the jobs each of them would be able to preform. Then, we can give each person a job suited to their abilities if, and only if, for every value of k (1...n), the union of any k of the lists contains at least k jobs.
is copied almost directly from the bottom of page 10 of the first reference. Ah -- by looking at the history it appears that Robert Borgersen has lifted the quoted paragraph from his own work. Is this ok, copyright-wise? Sam nead 19:49, 5 December 2005 (UTC)
- I can't see any problem with me using my own work as a reference. :) But maybe in the future, people will look and see that it was 'copied' from my work, and not notice that I wrote it. Feel free to reword it...or not...whatever. :) Rob 20:09, 5 December 2005 (UTC)
-
- Wikipedia is not the place to post original research. If you read a proof that Hall's theorem easily implies Menger's theorem then you should cite that proof. Don't cite your own work posted on the web. If you are the first person to prove that Hall's theorem implies Menger's theorem, then that is cool. Go publish in a combinatorics journal. Then cite the journal. Don't cite your own work posted on the web.
-
- I should add that I feel that self-plagiarism is bad form in Wikipedia and very bad form in academia. Don't do it. yours, Sam nead 04:12, 7 December 2005 (UTC)
- I can definately see how referencing yourself can be bad form, but what I've posted was nothing like original research. The paper I did was like a survey of these 7 theorems in combinatorics, and I reference at the end the papers/books I used. For me to copy and paste text that I wrote in a survey to another survey on the same topic (wikipedia can be looked at as a survey), whats wrong with it? Would you still consider it bad form? Maybe should I change it to an 'External Link' rather than a 'Reference'? Like saying 'Here is some info on this topic...here is a link with more info on this topic'. How's that sound? Or maybe I should copy and paste the references as well? Rob 23:48, 9 December 2005 (UTC)
Contents |
[edit] Question about (*)
While it's true that
and 
(by assumption), how does that allows us to say that
which is used at the end of the proof?
--71.226.232.199 17:24, 14 January 2006 (UTC)
It's also true that 
--12.72.245.95 13:06, 9 June 2006 (UTC)
Good point! I've removed the (*).
(128.112.139.195 04:46, 21 December 2006 (UTC))
[edit] The Konig-Egervary theorem
The Konig-Egervary theorem is the same thing as Konig's theorem, or so I thought. Maybe nowadays one name is used for the statement about bipartite graphs and the other for the (trivially equivalent) statement about 0-1 matrices: In a finite matrix (not necessarily square) whose coefficients are all 0 or 1, the minimum number of "lines" (meaning rows or columns, mixtures allowed) sufficient to cover all the 1's, is equal to the maximum number of 1's no two of which are on a common line. —Preceding unsigned comment added by LDH (talk • contribs)
- As far as I can tell from a quick Google, K-E refers to the matrix version, but as you say they are very easily equivalent, and the title "Gráfok és mátrixok" of König's 1931 paper suggests that he was well aware of the equivalence. Maybe it's so easy that K-E should be listed as a section in the König's theorem article, and the redlink redirected, rather than making a new article for it? One thing I'm not sure of, though, and would want to include, is who Egervary was and what contribution Egervary made to the problem. —David Eppstein 06:03, 22 February 2007 (UTC)
[edit] only if
The system says that there's an SDR iff the marriage condition holds. The proof gives the "if" direction, but not the "only if." (Of course the "only if" direction is trivial, but it should be stated!)
Eclecticos 04:40, 1 October 2007 (UTC)
[edit] Equivalence to Max Flow Min Cut
Any reference for why Hall's theorem is equivalent to the Max Flow Min Cut Theorem? The PDF linked to gives no answer. I just know how Hall follows from Max Flow Min Cut, but not the other way round - and in fact, the other way it seems pretty unlikely to me. —Preceding unsigned comment added by 217.233.151.120 (talk) 09:59, 4 October 2007 (UTC)
[edit] Reference is inaccessible
Gives me a 403. Is there any way to put that source somewhere publicly viewable (or get a different source altogether)?
Junocola (talk) 03:49, 1 May 2008 (UTC)
- I am shocked that my presentation is still here as a reference! I added it years ago now. Looking at it now, it's certainly not written the best, but I have updated the link. I am glad people are still finding it useful...maybe I will update it and write it a little better. Looking back at the conversation I had with people above years ago, I do now realize how silly it was of me to pull words out of my own work and post it here. I would not do that again. :) --Rob (talk) 00:22, 2 June 2008 (UTC)
