Source authenticatedTheorem 1.1: for arbitrary Coxeter systems (W,S) and (W′,S′), including infinite and noncrystallographic ones, and u≤b, u′≤b′, any poset isomorphism [u,b]→[u′,b′] gives Pu,bW=Pu′,b′W′ for the equal-parameter polynomials; restricting to subintervals determines every Px,y and, by reciprocity, every R-polynomial on the interval. The proof uses moment-graph sheaves (Braden-MacPherson, Fiebig, Elias-Williamson), an edge schedule transported from a reflection order of the second system, and Dyer's path formula. It gives no procedure computing P from the poset, and it treats equal parameters only.
Theorem 1.1: for arbitrary Coxeter systems (W,S) and (W′,S′), including infinite and noncrystallographic ones, and u≤b, u′≤b′, any poset isomorphism [u,b]→[u′,b′] gives Pu,bW=Pu′,b′W′ for the equal-parameter polynomials; restricting to subintervals determines every Px,y and, by reciprocity, every R-polynomial on the interval. The proof uses moment-graph sheaves (Braden-MacPherson, Fiebig, Elias-Williamson), an edge schedule transported from a reflection order of the second system, and Dyer's path formula. It gives no procedure computing P from the poset, and it treats equal parameters only.