A Combinatorial Proof of Vandermonde's Determinant

A Combinatorial Proof of Vandermonde's Determinant

that is as easy as playing cards. Let Vn denote the Vandermonde matrix with (i, j)th entry vi j = x j i (0 ≤ i, j ≤ n). Since the determinant of Vn is a polynomial in x0, x1, . . . , xn , it suffices to prove the identity for positive integers x0, x1, . . . , xn with x0 ≤ x1 ≤ · · · ≤ xn . We define a Vandermonde card to possess a suit and a value, where a card of Suit i has a value from the se...

A combinatorial determinant

A theorem of Mina evaluates the determinant of a matrix with entries D(f(x)). We note the important special case where the matrix entries are evaluated at x = 0 and give a simple proof of it, as well as some special additivity properties that hold in this case, but not in general. Some applications are given also. We then give a short proof of the general case. October 25, 1998 An old theorem o...

A combinatorial proof of Bass's determinant formula for the zeta function of regular graphs

We give an elementary combinatorial proof of Bass’s determinant formula for the zeta function of a finite regular graph. This is done by expressing the number of non-backtracking cycles of a given length in terms of Chebychev polynomials in the eigenvalues of the adjacency operator of the graph.

A Simple Combinatorial Proof of

A Combinatorial Determinant Dual to the Group Determinant

We define the commuting algebra determinant of a finite group action on a finite set, a notion dual to the group determinant of Dedekind. We show that the following combinatorial example is a commuting algebra determinant. Let Bq(n) denote the set of all subspaces of an n-dimensional vector space over Fq. The type of an ordered pair (U, V ) of subspaces, where U, V ∈ Bq(n), is the ordered tripl...