Stapledon's trivial-representation conjecture for equivariant Ehrhart coefficients

Let GG be a finite group, let MM be a lattice, let ρ:GAff(M)\rho:G\to\operatorname{Aff}(M) be an affine representation, and let PP be a GG-invariant lattice polytope. Assume that h(P,ρ;t)h^*(P,\rho;t) is a polynomial, and write h(P,ρ;t)mR(G)h^*(P,\rho;t)_m\in R(G) for the coefficient of tmt^m, where mm is any nonnegative integer. Stapledon's trivial-representation conjecture. If h(P,ρ;t)mh^*(P,\rho;t)_m is nonzero and effective, then the trivial representation occurs with nonzero multiplicity in h(P,ρ;t)mh^*(P,\rho;t)_m. The conjecture was verified for the symmetric-group action on the permutahedron, but the paper gives a counterexample, so it is refuted.

Sources & referencesView supporting material

Primary source

Alan Stapledon, “Equivariant Ehrhart theory, commutative algebra and invariant triangulations of polytopes”, arXiv:2311.17273 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.