A characterization of a special ordering in a root system

Papi, Paolo

doi:10.1090/S0002-9939-1994-1169886-7

A characterization of a special ordering in a root system
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by Paolo Papi PDF

Proc. Amer. Math. Soc. 120 (1994), 661-665 Request permission

Abstract:

We give necessary and sufficient conditions for an ordering of a set of positive roots in a root system $R$ to be associated to a reduced expression of an element of the Weyl group of $R$. Finally we characterize the sets of positive roots which can be given such an ordering.

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