Timeline for Postnikov system for a tree
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 29, 2013 at 19:42 | comment | added | Rajkarov | Thank you Mr Fernando for your responses. Actually I don't know I if this tower of graphs is postnikov system or not. But I understend the combinatoral prprieties of this graphs. for exemple every graph $X_{k}$ contain a loop and then it's not contractible. But we can taking a subgraphs $X_{k}^{x}$, where x is a point of the ends of X and $X_{k}^{x}$ is the subgraph of $X_{k}$ consists of the edges a such that there is a sequence $(s_{i})$ of vertex of X such that $(s_{0},...,s_{k+1})=a$ and $(s_{i})$ converge to x. I think that this tower of subgraphs is Postnikov System for $X$ . | |
| Jun 29, 2013 at 19:22 | comment | added | Rajkarov | I'm sorry Mr Lee for my bad english. It means the ends of the tree X, that is the set of semi-geodesic with basepoint s for a fixed vertex s of X. There is another definition of the ends of a tree or more genaraly of a graph. | |
| Jun 28, 2013 at 18:40 | comment | added | Lee Mosher | What does the phrase "points of the board of $X$" mean? | |
| Jun 28, 2013 at 17:34 | comment | added | Fernando Muro | What known properties of this tower of graphs make you suspect that it may be a Postnikov tower? Concerning your second question, there's a general procedure to construct Postnikov towers for arbitrary (nice enough) spaces, but usually it doesn't look very nice even if you apply it to a space you're familiar with. | |
| Jun 28, 2013 at 17:26 | history | asked | Rajkarov | CC BY-SA 3.0 |