Existence of Kirillov-Reshetikhin crystals for near adjoint nodes in exceptional types

Abstract

We prove that, in types $E_{6,7,8}^{(1)}$, $F_4^{(1)}$ and $E_6^{(2)}$, every Kirillov--Reshetikhin module associated with the node adjacent to the adjoint one (near adjoint node) has a crystal pseudobase, by applying the criterion introduced by Kang et.al. In order to apply the criterion, we need to prove some statements concerning values of a bilinear form. We achieve this by using the global bases of extremal weight modules.

39 pages. In version 1 the main theorem is proved in type $E_6^{(1)}$ only, but in version 2 and 3 we generalize the result in types $E_{6,7,8}^{(1)}$, $F_4^{(1)}$ and $E_6^{(2)}$. In version 3, some minor corrections are made