It is well-known that plane partitions, lozenge tilings of a hexagon, perfect matchings on a honeycomb graph, and families of non-intersecting lattice paths in a hexagon are all in bijection. In this work we consider regions that are more general than hexagons. They are obtained by further removing upward-pointing triangles. We call the resulting shapes triangular regions. We establish signed versions of the latter three bijections for triangular regions. We first investigate the tileability of triangular regions by lozenges. Then we use perfect matchings and families of non-intersecting lattice paths to define two signs of a lozenge tiling. Using a new method that we call resolution of a puncture, we show that the two signs are in fact equivalent. As a consequence, we obtain the equality of determinants, up to sign, that enumerate signed perfect matchings and signed families of lattice paths of a triangular region, respectively. We also describe triangular regions, for which the signed enumerations agree with the unsigned enumerations.
@article{10_37236_5579,
author = {D. Cook II and Uwe Nagel},
title = {Signed lozenge tilings},
journal = {The electronic journal of combinatorics},
year = {2017},
volume = {24},
number = {1},
doi = {10.37236/5579},
zbl = {1360.52014},
url = {http://geodesic.mathdoc.fr/articles/10.37236/5579/}
}
TY - JOUR
AU - D. Cook II
AU - Uwe Nagel
TI - Signed lozenge tilings
JO - The electronic journal of combinatorics
PY - 2017
VL - 24
IS - 1
UR - http://geodesic.mathdoc.fr/articles/10.37236/5579/
DO - 10.37236/5579
ID - 10_37236_5579
ER -
%0 Journal Article
%A D. Cook II
%A Uwe Nagel
%T Signed lozenge tilings
%J The electronic journal of combinatorics
%D 2017
%V 24
%N 1
%U http://geodesic.mathdoc.fr/articles/10.37236/5579/
%R 10.37236/5579
%F 10_37236_5579
D. Cook II; Uwe Nagel. Signed lozenge tilings. The electronic journal of combinatorics, Tome 24 (2017) no. 1. doi: 10.37236/5579
