The parity of the Cochran-Harvey invariants of 3-manifolds

Stefan Friedl; Taehee Kim

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The parity of the Cochran-Harvey invariants of 3-manifolds

Stefan Friedl·Taehee Kim

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Abstract

Given a finitely presented group G and an epimorphism G to the group of integers Cochran and Harvey defined a sequence of integral invariants, which can be viewed as the degrees of higher--order Alexander polynomials. Cochran and Harvey showed that (up to a minor modification) this is a never decreasing sequence of numbers if G is the fundamental group of a 3-manifold with empty or toroidal boundary, and that these invariants give lower bounds on the Thurston norm. Using a certain Cohn localization and the duality of Reidemeister torsion we show that for a fundamental group of a 3--manifold any jump in the sequence is necessarily even. This answers in particular a question of Cochran. Furthermore using results of Turaev we show that under a mild extra hypothesis the parity of the Cochran--Harvey invariant agrees with the parity of the Thurston norm.

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BibTeX RIS

Stefan Friedl, Taehee Kim. 2006-02-18. The parity of the Cochran-Harvey invariants of 3-manifolds. https://arxiv.org/abs/math/0510475

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