Homotopy Type of Intervals of the Second Higher Bruhat Orders

The higher Bruhat order is a poset generalizing the weak order on permutations. Another special case of this poset is an ordering on simple wiring diagrams. For this case, we prove that every interval is either contractible or homotopy equivalent to a sphere. This partially proves a conjecture due t...

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Bibliographic Details
Main Author: McConville, Thomas
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Language:English
Published: Springer Netherlands 2018
Online Access:http://hdl.handle.net/1721.1/119674
https://orcid.org/0000-0001-9276-4291
Description
Summary:The higher Bruhat order is a poset generalizing the weak order on permutations. Another special case of this poset is an ordering on simple wiring diagrams. For this case, we prove that every interval is either contractible or homotopy equivalent to a sphere. This partially proves a conjecture due to Reiner. Our proof uses some tools developed by Felsner and Weil to study wiring diagrams. Keywords: Higher Bruhat, Order complex, Mobius function, Wiring diagram, Rhombic tiling