The Coxeter polynomial of $P$ is the characteristic polynomial of the Coxeter transformation matrix $ -M M^{-t}$, where $M$ is the relation matrix. This depends only on the derived category of modules over the incidence algebra.
i1 : B = booleanLattice 3; |
i2 : z = coxeterPolynomial B
8 7 6 5 4 3 2
o2 = t + t + t - 2t - 2t - 2t + t + t + 1
o2 : ZZ[t]
|
The object coxeterPolynomial is a method function with options.