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The Euler characteristic of the Whitehead automorphism group of a free product

Craig Jensen·Jon McCammond·John Meier
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Abstract

A combinatorial summation identity over the lattice of labelled hypertrees is established that allows one to gain concrete information on the Euler characteristics of various automorphism groups of free products of groups.

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Craig Jensen, Jon McCammond, John Meier. 2006-01-28. The Euler characteristic of the Whitehead automorphism group of a free product. https://arxiv.org/abs/math/0601694

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