Talk:Singular homology
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(misc questions)
- Header added. —Nils von Barth (nbarth) (talk) 21:08, 26 July 2009 (UTC)
Why does singular cohomology link to this page, if cohomology is never mentioned? 3:58 PM CST 28 Dec 2004.
I think a table of common homology groups or a link to one (should someone know where one might be found) would be very useful. Alexwright 19:57, 29 November 2006 (UTC)
What is Z_n in the section "Singular chain complex". It seems to be invoked without having ever been defined. Should it be C_n? Or do you mean the center of something?72.69.194.235 (talk) 21:15, 28 November 2009 (UTC)
May defines C_n to be on the nondegenerate singular simplices. Perhaps the article should mention alternative definitinos?165.124.97.20 (talk) 18:43, 16 May 2011 (UTC)
Homotopy invariance
I don't understand a step in the proof of homotopy invariance and I hope someone can clarify it. The issue is the definition of the map $P$. I have two questions about it:
- How is it related to the map $F$? It needs to have some relation to $F$ otherwise it is useless, right?
- It says $P: C_n \to C_{n+1}$. From this I would expect the domain of $P(\sigma)$ to be a $(n+1)$-simplex. Instead it is a prism. How is this possible? Are prisms secretly also simplices?
I don't know the answer to these questions - I hope someone else does and can update the article Octonion (talk) 11:17, 24 May 2025 (UTC)