Classification of cocovers in the double affine Bruhat order (Q2094873)

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scientific article; zbMATH DE number 7613662
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Classification of cocovers in the double affine Bruhat order
scientific article; zbMATH DE number 7613662

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    Classification of cocovers in the double affine Bruhat order (English)
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    8 November 2022
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    Summary: We classify cocovers of a given element of the double affine Weyl semigroup \(W_{\mathcal{T}}\) with respect to the Bruhat order, specifically when \(W_{\mathcal{T}}\) is associated to a finite root system that is irreducible and simply laced. We do so by introducing a graphical representation of the length difference set defined by \textit{D. Muthiah} and \textit{D. Orr} [Algebr. Comb. 2, No. 2, 197--216 (2019; Zbl 1414.05304)] and identifying the cocovering relations with the corners of those graphs. This new method allows us to prove that there are finitely many cocovers of each \(x \in W_{\mathcal{T}}\). Further, we show that the Bruhat intervals in the double affine Bruhat order are finite.
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    double affine Weyl semigroup
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    double affine Bruhat order
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