32 Incidence numbers of the cellular chain complex

This is episode 32 of a course on algebraic topology.

Erratum: At 09:28, the (n-1)-st singular homology functor should carry a "twiddle" on top. One needs to use reduced homology to get the correct incidence matrix also for n=1.

Outline:
00:00 Start
08:08 Def.: Incidence number
12:58 Thm.: A Commutative diagram