Talk:Relative homology
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Could someone add relative cohomology? Charles Matthews 21:32, 19 October 2005 (UTC)
What is the definition of a morphism of pairs of topological spaces (as implied by the reference to a "category" of such pairs)? - 74.112.133.181 01:29, 12 May 2007 (UTC)
- If (X,A) and (X',A') are both pairs, then a morphism between them is a continuous map which maps A to (a subset of) A'. - Saibod 18:33, 14 May 2007 (UTC)
Is it always true that or only when ? 69.234.22.18 21:09, 19 October 2007 (UTC)
- only when n ≠ 0. the equality is true for all n if the right hand side is replaced by reduced homology. Mct mht (talk) 10:56, 14 December 2007 (UTC)
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- This should be made clear in the article. I'll edit it to reflect that. Hurkyl (talk) 04:08, 21 February 2008 (UTC)