The discrete LS algebra over a totally ordered set is the homogeneous
coordinate ring of an irreducible projective (normal) toric variety. We prove
that this algebra is the ring of invariants of a finite abelian group
containing no pseudo-reflection acting on a polynomial ring. This is used to
study the Gorenstein property for LS algebras. Further we show that any LS
algebra is Koszul.Comment: 11 pages, minor editing in references, accepted by Communications in
Contemporary Mathematic
