Acta Mathematica

Existence and uniqueness of linking systems: Chermak’s proof via obstruction theory

Bob Oliver

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We present a version of a proof by Andy Chermak of the existence and uniqueness of centric linking systems associated with arbitrary saturated fusion systems. This proof differs from the one in [Ch2] in that it is based on the computation of derived functors of certain inverse limits. This leads to a much shorter proof, but one which is aimed mostly at researchers familiar with homological algebra.


The author was partially supported by the DNRF through a visiting professorship at the Centre for Symmetry and Deformation in Copenhagen; and also by UMR 7539 of the CNRS and by project ANR BLAN08-2 338236, HGRT.

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Acta Math., Volume 211, Number 1 (2013), 141-175.

Received: 25 August 2011
Revised: 26 January 2013
First available in Project Euclid: 31 January 2017

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2013 © Institut Mittag-Leffler


Oliver, Bob. Existence and uniqueness of linking systems: Chermak’s proof via obstruction theory. Acta Math. 211 (2013), no. 1, 141--175. doi:10.1007/s11511-013-0100-3.

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