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Template:Analogous fixed-point theorems

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There are several fixed-point theorems which come in three equivalent variants: an algebraic topology variant, a combinatorial variant and a set-covering variant. Each variant can be proved separately using totally different arguments, but each variant can also be reduced to the other variants in its row. Additionally, each result can be reduced to the other result in its column.[1]

Algebraic topology Combinatorics Set covering
Brouwer fixed-point theorem Sperner's lemma KKM lemma
Borsuk–Ulam theorem Tucker's lemma Lusternik–Schnirelmann theorem
  1. ^ Nyman, Kathryn L.; Su, Francis Edward (2013), "A Borsuk-Ulam equivalent that directly implies Sperner's lemma", American Mathematical Monthly, 120 (4): 346–354, doi:10.4169/amer.math.monthly.120.04.346, MR 3035127