A Root System Criterion for Fully Commutative and Short Braid-Avoiding Elements in Affine Weyl Groups
نویسنده
چکیده
We provide simple characterizations of short-braid avoiding and fully commutative elements in an affine Weyl group W , generalizing results of Fan and Stembridge for finite Weyl groups. Our results rely on the combinatorics of the compatible subsets of the root system of W .
منابع مشابه
On 321-Avoiding Permutations in Affine Weyl Groups
We introduce the notion of 321-avoiding permutations in the affine Weyl group W of type An−1 by considering the group as a George group (in the sense of Eriksson and Eriksson). This enables us to generalize a result of Billey, Jockusch and Stanley to show that the 321-avoiding permutations in W coincide with the set of fully commutative elements; in other words, any two reduced expressions for ...
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