Enumerating indices of Schubert varieties defined by inclusions

Abstract

By extending the notion of grid classes to include infinite grids, we establish a structural characterisation of the simple permutations in Av(4231, 35142, 42513, 351624), a pattern class which has three different connections with algebraic geometry, including the specification of indices of Schubert varieties defined by inclusions. This characterisation leads to the enumeration of the class.

14 pages, 3 figures. Accepted in Journal of Combinatorial Theory, Series A

References in corpus (1)

• The enumeration of permutations avoiding 2143 and 4231

Cited by in corpus (1)

• Counting matrices over finite fields with support on skew Young diagrams and complements of Rothe diagrams