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COHERENCE, LOCAL INDICABILITY AND NONPOSITIVE IMMERSIONS

Published online by Cambridge University Press:  17 September 2020

Daniel T. Wise*
Affiliation:
Dept. of Math. & Stats., McGill University, Montreal, QuebecH3A 2K6, Canada ([email protected])

Abstract

We examine 2-complexes $X$ with the property that for any compact connected $Y$, and immersion $Y\rightarrow X$, either $\unicode[STIX]{x1D712}(Y)\leqslant 0$ or $\unicode[STIX]{x1D70B}_{1}Y=1$. The mapping torus of an endomorphism of a free group has this property. Every irreducible 3-manifold with boundary has a spine with this property. We show that the fundamental group of any 2-complex with this property is locally indicable. We outline evidence supporting the conjecture that this property implies coherence. We connect the property to asphericity. Finally, we prove coherence for 2-complexes with a stricter form of this property. As a corollary, every one-relator group with torsion is coherent.

Type
Research Article
Copyright
© The Author(s) 2020. Published by Cambridge University Press

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Footnotes

Research supported by NSERC.

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