Palindromic decomposition conjecture for symmetric edge-polytope edge deletion

From papers

Let GG be a 2-connected graph and let ijij be any edge of GG. Let Γ\Gamma be a unimodular triangulation of the subcomplex of PGijP_{G\setminus ij} consisting of all facets visible by eije_{ij}. If the distinct lattice distances from eije_{ij} to facets of Γ\Gamma are h1>h2>>hkh_1>h_2>\cdots>h_k, define

Γs:=σ facet of Γhσhs\Gamma_s:=\langle\sigma\text{ facet of }\Gamma\mid h_\sigma\ge h_s\rangle

for s=1,,ks=1,\ldots,k, and set hΓ0(t):=0h_{\Gamma_0}(t):=0. Palindromic decomposition conjecture.

hPG(t)hPGij(t)=2ts=1k((hΓs(t)hΓs1(t))r=0hs1tr).h^*_{P_G}(t)-h^*_{P_{G\setminus ij}}(t)=2t\sum_{s=1}^{k}\left(\left(h_{\Gamma_s}(t)-h_{\Gamma_{s-1}}(t)\right)\sum_{r=0}^{h_s-1}t^r\right).

Moreover, for every s=1,,ks=1,\ldots,k, the polynomial

(hΓs(t)hΓs1(t))r=0hs1tr\left(h_{\Gamma_s}(t)-h_{\Gamma_{s-1}}(t)\right)\sum_{r=0}^{h_s-1}t^r

is palindromic, has nonnegative coefficients, and has the same center as the left-hand side. This proposed formula would decompose the edge-deletion difference into palindromic pieces with nonnegative coefficients; the supplied text gives no resolution status.

Progress summary

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

Sources & referencesView supporting material

Primary source

Giulia Codenotti, Roberto Riccardi and Lorenzo Venturello, “The number of edges of a symmetric edge polytope”, arXiv:2512.16572 (2026).

Solutions 0

No solutions have been posted yet.