Properties
Homotopy invariance: Let ƒ, g: X → Y be homotopy equivalences of finite connected CW-complexes. If ƒ and g are homotopic then τ(ƒ) = τ(g).
Topological invariance: If ƒ: X → Y is a homeomorphism of finite connected CW-complexes then τ(ƒ) = 0.
Composition formula: Let ƒ: X → Y, g: Y → Z be homotopy equivalences of finite connected CW-complexes. Then .
Read more about this topic: Whitehead Torsion
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—John Locke (1632–1704)
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