I am renaming this entry from “long exact sequence in homology” to “long exact sequence in chain homology”.

This is to make room for a long missing entry on the long exact sequence in generalized homology.

]]>I wrote something at *homology long exact sequence – Relation to homotopy fiber sequences*.

This overlaps with stuff that is alreay mentioned at *fiber sequence*, but I want a more elementary exposition here focused on chain complexes.

I am beginning to split off from *fiber sequence* an entry *long exact sequence in homology* (also splitting off all the related redirects, such as long exact sequence in cohomology etc).