Rank two and a positivity conjecture
Arun Ram
Department of Mathematics and Statistics
University of Melbourne
Parkville, VIC 3010 Australia
aram@unimelb.edu.au
Last update: 25 February 2013
Rank two and a positivity conjecture
In this section we will give explicit formulas for the rank two root systems. The data supports the following positivity conjecture which generalizes the theorems of
Brion [Bri2002, formula before Theorem 1] and Graham [Gra9908172, Corollary 4.1].
Conjecture 5.9.
For let
and
and let
for Let
be the structure constants of with respect to the basis
as defined in (0.1). Then
that is, is a polynomial in the variables
and
which has non-negative integral coefficients.
In the following, for brevity, use the following notations:
and in and in
the terms in brackets do not appear.
Type
For the root system of type
Formulas for the Schubert classes in terms of homogeneous line bundles can be given by
and
The multiplication of the Schubert classes is given by
Type For the root system of type
Formulas for the Schubert classes in terms of homogeneous line bundles can be given by
and
The multiplication of the Schubert classes is given by
Type For the root system of type
Formulas for the Schubert classes in terms of homogeneous line bundles can be given by
and
The multiplication of the Schubert classes is given by
Notes and References
This is an excerpt of the paper entitled Affine Hecke algebras and the Schubert calculus authored by Stephen Griffeth and Arun Ram. It was dedicated to Alain Lascoux.
page history