Generalization of matching extensions in graphs—combinatorial interpretation of orthogonal and q-orthogonal polynomials

Abstract

In this paper, we present generalization of matching extensions in graphs and we derive combinatorial interpretation of wide classes of orthogonal and q-orthogonal polynomials. Specifically, we assign general weights to complete graphs, cycles and chains or paths defining matching extensions in these graphs. The generalized matching polynomials of these graphs have recurrences defining various orthogonal polynomials—including classical and non-classical ones—as well as q-orthogonal polynomials. The Hermite, Gegenbauer, Legendre, Chebychev of the first and second kind, Jacobi and Pollaczek orthogonal polynomials and the continuous q-Hermite, Big q-Jacobi, Little q-Jacobi, Al Salam and alternative q-Charlier q-orthogonal polynomials appeared as applications of this study.