arXiv · 2305.12613
If G is a finite abstract simplicial complex and K is a subcomplex of G and U=G-K is the open complement of K in G, the Betti vectors of K and U and G satisfy the inequality b(G) less or equal b(K)+b(U).
Oliver Knill. 2023-05-22. Cohomology of open sets. https://arxiv.org/abs/2305.12613
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