Impact
~1k
people reached
- 0 posts edited
- 0 helpful flags
- 4 votes cast
Mar
4 |
comment |
Is there a polynomial-time algorithm to check if a signed graph contains an odd-K5 minor?
@TonyHuynh, many thanks for your help! Do you know if there's some kind of generalization of Guenin's result (characterizing weakly bipartite signed graphs) to the more general setting you've looked at, with $\Gamma$-labeled graphs? |
Feb
17 |
accepted | Is there a polynomial-time algorithm to check if a signed graph contains an odd-K5 minor? |
Feb
17 |
revised |
Is there a polynomial-time algorithm to check if a signed graph contains an odd-K5 minor?
edited tags |
Feb
17 |
asked | Is there a polynomial-time algorithm to check if a signed graph contains an odd-K5 minor? |
Jan
5 |
revised |
Is there a version of Robertson-Seymour's graph minor theorem known to apply to signed graphs?
deleted 4 characters in body |
Jan
5 |
comment |
Is there a version of Robertson-Seymour's graph minor theorem known to apply to signed graphs?
Exactly. @Tony, many thanks for your clarifications and answer. |
Jan
3 |
accepted | Is there a version of Robertson-Seymour's graph minor theorem known to apply to signed graphs? |
Jan
2 |
asked | Is there a version of Robertson-Seymour's graph minor theorem known to apply to signed graphs? |
Jul
10 |
revised |
Convergence rate of iterated nonlinear equations?
fixed small format error |
Jun
19 |
comment |
Reference request for: inverse of a non-singular M-matrix has all elements non-negative?
Fan 1958, Theorem 5' in "Topological proofs for certain theorems on matrices with non-negative elements..." is now the earliest reference I can find. |
Jun
19 |
comment |
Reference request for: inverse of a non-singular M-matrix has all elements non-negative?
Thanks Dmitry. Looking there and the refs given, Fiedler and Ptak 1962 provide a proof without referencing an earlier result, though earlier work by Ostrowski, Fan, Koteljansku and Minkowski are mentioned, and I imagine one of those probably proved this result earlier. |
Jun
19 |
comment |
Reference request for: inverse of a non-singular M-matrix has all elements non-negative?
Sorry, you're right, now fixed. As you say, it's an old topic. The result may be found in several places but I'd like to reference the original result if possible. |
Jun
19 |
revised |
Reference request for: inverse of a non-singular M-matrix has all elements non-negative?
added 15 characters in body |
Jun
18 |
asked | Reference request for: inverse of a non-singular M-matrix has all elements non-negative? |
May
25 |
comment |
Perturbed linear system, particular form
Hi Frederico, I was not familiar with the term but from reading Wikipedia en.wikipedia.org/wiki/Stieltjes_matrix yes - sorry, I have added the important point that we may assume A is positive definite, hence is a Stieltjes matrix (and hence an M-matrix). Are relevant results known for such? Thanks for any help. |
May
25 |
revised |
Perturbed linear system, particular form
clarification |
May
25 |
revised |
Perturbed linear system, particular form
Minor correction |
May
25 |
revised |
Perturbed linear system, particular form
added 7 characters in body |
May
25 |
revised |
Perturbed linear system, particular form
added 29 characters in body |
May
25 |
revised |
Perturbed linear system, particular form
added 45 characters in body |