Identities of the multi-variate independence polynomials from heaps theory

We study and derive identities for the multi-variate independence polynomials from the perspective of heaps theory. Using the inversion formula and the combinatorics of partially commutative algebras we show how the multi-variate version of Godsil type identity as well as the fundamental identity can be obtained from weight preserving bijections. Finally, we obtain a multi-variate identity involving connected bipartite subgraphs similar to the Christoffel–Darboux type identities obtained by Bencs.