The isomorphism problem of planar polygon spaces

Dirk Schuetz

doi:10.1112/jtopol/jtq024

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arXiv · 0906.4499

The isomorphism problem of planar polygon spaces

Dirk Schuetz

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Abstract

We give a proof of a Conjecture of Walker which states that one can recover the lengths of the bars of a circular linkage from the cohomology ring of the configuration space. For a large class of length vectors, this has been shown by Farber, Hausmann and Schuetz. In the remaining cases, we use Morse theory and the fundamental group to describe a subring of the cohomology invariant under graded ring isomorphism. From this subring the conjecture can be derived by applying a result of Gubeladze on the isomorphism problem of monoidal rings.

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Dirk Schuetz. 2009-06-24. The isomorphism problem of planar polygon spaces. https://doi.org/10.1112/jtopol%2Fjtq024

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