nLab A mechanization of the Blakers-Massey connectivity theorem in Homotopy Type Theory

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on a formal proof of the Blakers-Massey theorem in homotopy type theory.

Abstract. This paper continues investigations in “synthetic homotopy theory”: the use of homotopy type theory to give machine-checked proofs of constructions from homotopy theory. We present a mechanized proof of the Blakers-Massey connectivity theorem, a result relating the higher-dimensional homotopy groups of a pushout type (roughly, a space constructed by gluing two spaces along a shared subspace) to those of the components of the pushout. This theorem gives important information about the pushout type, and has a number of useful corollaries, including the Freudenthal suspension theorem, which has been studied in previous formalizations. The new proof is more elementary than existing ones in abstract homotopy-theoretic settings, and the mechanization is concise and high-level, thanks to novel combinations of ideas from homotopy theory and type theory.

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category: reference

Last revised on June 9, 2022 at 15:00:07. See the history of this page for a list of all contributions to it.