Timeline for How does singular homology H_n capture the number of n-dimensional "holes" in a space?
Current License: CC BY-SA 2.5
7 events
| when toggle format | what | by | license | comment | |
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| Jul 7, 2010 at 1:16 | history | edited | Jose Brox |
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| May 23, 2010 at 17:40 | vote | accept | Akela | ||
| May 15, 2010 at 5:52 | answer | added | Emerton | timeline score: 11 | |
| May 15, 2010 at 5:43 | comment | added | Emerton | Mayer-Vietoris predates the snake lemma, if I have my history correct, and is quite geometric: if $X = U \cup V$ and $\tau$ is a cycle in $X$, then you cut it along the interface between $U$ and $V$ to obtain a chain $\tau'$ lying in $U$, which may no longer be a cycle; so you take its boundary, which will lie in $U\cap V$. (Draw a picture.) This is the map from $H_i(X)$ to $H_{i-1}(U\cap V)$. The other maps in the long exact sequence are similarly geometric. If this is not clear from the text you are using, than I suggest you find another text. | |
| May 13, 2010 at 9:49 | comment | added | Zbigniew Błaszczyk | Have you seen the (sub)section "The Idea of Homology" of Hatcher's book? It helped me a lot. | |
| May 13, 2010 at 2:49 | answer | added | Mariano Suárez-Álvarez | timeline score: 6 | |
| May 12, 2010 at 23:50 | history | asked | Akela | CC BY-SA 2.5 |