Algebraic Topology · Problem 2C.8

Cohomology — Allen Hatcher

Mathematics — Topology · countably-many-homotopy-classes

Problem

Let XX be homotopy equivalent to a finite simplicial complex and let YY be homotopy equivalent to a finite or countably infinite simplicial complex. Using the simplicial approximation theorem, show that there are at most countably many homotopy classes of maps X→YX \to Y.

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