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arXiv · 1302.1052

Denominator vectors and compatibility degrees in cluster algebras of finite type

Cesar Ceballos·Vincent Pilaud
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Abstract

We present two simple descriptions of the denominator vectors of the cluster variables of a cluster algebra of finite type, with respect to any initial cluster seed: one in terms of the compatibility degrees between almost positive roots defined by S. Fomin and A. Zelevinsky, and the other in terms of the root function of a certain subword complex. These descriptions only rely on linear algebra. They provide two simple proofs of the known fact that the denominator vector of any non-initial cluster variable with respect to any initial cluster seed has non-negative entries and is different from zero.

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Cesar Ceballos, Vincent Pilaud. 2013-02-05. Denominator vectors and compatibility degrees in cluster algebras of finite type. https://doi.org/10.1090/s0002-9947-2014-06239-9

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