4 papers · 1 filter
Integral homology lattices of matching and circulant complexes
Qihang Wang, Weiye Li
Bouc's hook cycles span the rational top homology of the matching complex of . We prove that their integral saturation quotient has exponent exactly $2^{\lfloor k/2\rfloo…
Cotangent cohomology and higher-order obstructions of matroids
Qihang Wang
Matroid Stanley-Reisner rings admit essential deformation obstructions of arbitrarily high order over every field, already at corank three. For each , we construct a connect…
-Zeta positivity for root and Ferrers-cell posets
Qihang Wang, Weiye Li
We prove that Chapoton's -Zeta numerator has nonnegative coefficients for the positive-root poset of every finite reduced irreducible crystallographic root system, graded by roo…
Four Special Directions over Prime Fields: Structure and Complete Classification
Qihang Wang
A direction of the affine plane is special for a set if the lines in that direction do not all meet the set in the same number of points. We classify, for every pr…