| | |
| | |
Stat |
Members: 3645 Articles: 2'503'724 Articles rated: 2609
23 April 2024 |
|
| | | |
|
Article overview
| |
|
Chromatic numbers, morphism complexes, and Stiefel-Whitney characteristic classes | Dmitry N. Kozlov
; | Date: |
26 May 2005 | Subject: | Algebraic Topology; Combinatorics MSC-class: 05C15; 55T99, 57M15, 68R10 | math.AT math.CO | Abstract: | Combinatorics, in particular graph theory, has a rich history of being a domain of successful applications of tools from other areas of mathematics, including topological methods. Here, we survey the study of the Hom-complexes, and the ways these can be used to obtain lower bounds for the chromatic numbers of graphs, presented in a recent series of papers cite{BK03a,BK03b,BK03c,CK1,CK2,K4,K5}. The structural theory is developed and put in the historical context, culminating in the proof of the Lovász Conjecture, which can be stated as follows: For a graph G, such that the complex Hom(C_{2r+1},G) is k-connected for some integers r>0 and k>-2, we have chi(G)>k+3. Beyond the, more customary in this area, cohomology groups, the algebro-topological concepts involved are spectral sequences and Stiefel-Whitney characteristic classes. Complete proofs are included for all the new results appearing in this survey for the first time. | Source: | arXiv, math.AT/0505563 | Services: | Forum | Review | PDF | Favorites |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
browser Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)
|
| |
|
|
|
| News, job offers and information for researchers and scientists:
| |