3 papers
math.GR2026
Parabolic Normalizers in Finite Coxeter Groups as Subdirect Products
J. Matthew Douglass, Götz Pfeiffer, Gerhard Roehrle
We revisit the structure of the normalizer of a parabolic subgroup in a finite Coxeter group , originally described by Howlett. Building on Howlett's Lemma, which p…
math.AG2025
The Leray-Hirsch Theorem for equivariant oriented cohomology of flag varieties
J. Matthew Douglass, Changlong Zhong
We use the formal affine Demazure algebra to construct an explicit Leray-Hirsch Theorem for torus equivariant oriented cohomology of flag varieties. We then generalize the Borel mo…
math.RT2025
Invariants and semi-invariants in the cohomology of the complement of a reflection arrangement
J. Matthew Douglass, Goetz Pfeiffer, Gerhard Roehrle
Suppose V is a finite dimensional, complex vector space, A is a finite set of codimension one subspaces of V, and G is a finite subgroup of the general linear group GL(V) that perm…