Timeline for Why do wedges of spheres often appear in combinatorics?
Current License: CC BY-SA 3.0
7 events
| when toggle format | what | by | license | comment | |
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| Nov 17, 2013 at 20:05 | comment | added | Russ Woodroofe | Indeed, one could view algebraic shifting as saying that any simplicial complex can be slightly perturbed (for a particular algebraic, complicated notion of 'perturbed') to become a bouquet of spheres. | |
| Nov 15, 2013 at 3:39 | history | edited | Matthew Kahle | CC BY-SA 3.0 |
corrected typo
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| Nov 14, 2013 at 21:33 | comment | added | Matthew Kahle | Dear Gil, this is certainly true for random $Q$-acyclic complexes, as you showed in your beautiful paper. But I think for Bernoulli random $d$-complexes of Linial-Meshulam-Wallach, for example, there should only be a relatively small range of $p$ where we see torsion. If it there at all, I expect to only see it when $p = c/n$. Certainly it can't happen when $p \ll 1/n$ or when $p \gg \log n / n$. | |
| Nov 14, 2013 at 21:28 | history | edited | Matthew Kahle | CC BY-SA 3.0 |
updated with new results
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| Sep 23, 2010 at 1:02 | comment | added | Gil Kalai | there are various indications that various random simplicial complexes will have huge torsions in their homology groups. So they will not be even homologically (w.r.t. Z) wedge of spheres. | |
| Sep 23, 2010 at 0:06 | history | edited | Matthew Kahle | CC BY-SA 2.5 |
deleted 2 characters in body
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| Sep 22, 2010 at 20:29 | history | answered | Matthew Kahle | CC BY-SA 2.5 |