SAGBI bases for rings of invariant Laurent polynomials

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Sagbi Bases for Rings of Invariant Laurent Polynomials

Let k be a field, Ln = k[x ±1 1 , . . . , x ±1 n ] be the Laurent polynomial ring in n variables and G be a group of k-algebra automorphisms of Ln. We give a necessary and sufficient condition for the ring of invariants Ln to have a SAGBI basis. We show that if this condition is satisfied then Ln has a SAGBI basis relative to any choice of coordinates in Ln and any term order.

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ژورنال

عنوان ژورنال: Proceedings of the American Mathematical Society

سال: 2008

ISSN: 0002-9939

DOI: 10.1090/s0002-9939-08-09538-5