Multiplicative formulas in Cohomology of $G/P$ and in quiver representations
Abstract
Description
Consider a partial flag variety $X$ which is not a grassmaninan. Consider also its cohomology ring ${\rm H}^*(X,\ZZ)$ endowed with the base formed by the Poincaré dual classes of the Schubert varieties. In \cite{Richmond:recursion}, E. Richmond showed that some coefficient structure of the product in ${\rm H}^*(X,\ZZ)$ are products of two such coefficients for smaller flag varieties. Consider now a quiver without oriented cycle. If $α$ and $β$ denote two dimension-vectors, $α\circβ$ denotes the number of $α$-dimensional subrepresentations of a general $α+β$-dimensional representation. In \cite{DW:comb}, H. Derksen and J. Weyman expressed some numbers $α\circβ$ as products of two smaller such numbers. The aim of this work is to prove two generalisations of the two above results by the same way.
The main result of this note was obtained simultenously by E. Richmond (see arXiv:0812.1856)
The main result of this note was obtained simultenously by E. Richmond (see arXiv:0812.1856)