2-enumerations of halved alternating sign matrices
arXiv:math/0106038
Abstract
We compute 2-enumerations of certain halved alternating sign matrices. In one case the enumeration equals the number of perfect matchings of a halved Aztec diamond. In the other case the enumeration equals the number of perfect matchings of a halved fortress graph. Our results prove three conjectures by Jim Propp.
11 pages, AmS-LaTeX, uses TeXDraw