How do we prove isomorphic complexes have the same cohomology?
If C. and D. are isomorphic, how do we prove
so we need an isomorphism for:
where , are the differentiations for C. and D. respectively.
I think we must use the individual isomorphisms to find some property/relation between the kernels in each of the exact sequences, and same for the images. I found such properties, just can't see how to finish by constructing the isomorphism!
Thanks in advance