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arXiv · 1804.02761

Tamari Lattices for Parabolic Quotients of the Symmetric Group

Henri Mühle·Nathan Williams
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Abstract

We generalize the Tamari lattice by extending the notions of $231$-avoiding permutations, noncrossing set partitions, and nonnesting set partitions to parabolic quotients of the symmetric group $\mathfrak{S}_{n}$. We show bijectively that these three objects are equinumerous. We show how to extend these constructions to parabolic quotients of any finite Coxeter group. The main ingredient is a certain aligned condition of inversion sets; a concept which can in fact be generalized to any reduced expression of any element in any (not necessarily finite) Coxeter group.

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Henri Mühle, Nathan Williams. 2019-11-01. Tamari Lattices for Parabolic Quotients of the Symmetric Group. https://doi.org/10.37236/7844

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