PD₄-complexes with π₂ a projective ℤ[π₁]-module

2026/06/28 by Jonathan A. Hillman
Mathematics · #math.GT

paper · pdf

Abstract

Let X be a PD₄-complex and let π=π₁(X). If π is torsion-free and π₂(X) is a finitely generated projective ℤ[π]-module then either π is free or π is FP and c.d.π=4. If, moreover, H³(π;ℤ[π])=0 then π is a free product of PD₄-groups and a free group.

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