Proceedings of the London Mathematical Society Advance Access originally published online on December 10, 2007
Proceedings of the London Mathematical Society 2008 96(3):582-622; doi:10.1112/plms/pdm034
| ||||||||||||||||||||||||||||||||||||||||||||||||||
© 2007 London Mathematical Society
Crystal structure on the set of Lakshmibai–Seshadri paths of an arbitrary level-zero shape
Institute of Mathematics
University of Tsukuba
Tsukuba
Ibaraki 305-8571
Japan
naito@math.tsukuba.ac.jp
Received 14 November 2006.
Let
, with mi

0 for i
I0, be a level-zero dominant integral weight for an affine Lie algebra
over
, where the
i, i
I0, are the level-zero fundamental weights, and let
(
) be the crystal of all Lakshmibai–Seshadri paths of shape
. First, we give an explicit description of the decomposition of the crystal
(
) into connected components and show that all the connected components are pairwise isomorphic (up to a shift of weights). Second, we realize the connected component
0(
) of
(
) containing the straight line 
as a specified subcrystal of the affinization
(with weight lattice P) of the crystal
(with weight lattice
, where
is the null root of
), which we studied in a previous paper (Int. Math. Res. Not. 2005 (2005) 815–840).
2000 Mathematics Subject Classification 17B37, 05E99 (primary); 81R10, 81R50 (secondary).