The Inverse Rook Problem on Ferrers Boards
نویسنده
چکیده
Rook polynomials have been studied extensively since 1946, principally as a method for enumerating restricted permutations. However, they have also been shown to have many fruitful connections with other areas of mathematics, including graph theory, hypergeometric series, and algebraic geometry. It is known that the rook polynomial of any board can be computed recursively. [19, 18] The naturally arising inverse question — given a polynomial, what board (if any) is associated with it? — remains open. In this paper, we solve the inverse problem completely for the class of Ferrers boards, and show that the increasing Ferrers board constructed from a polynomial is unique.
منابع مشابه
Rook Poset Equivalence of Ferrers Boards
A natural construction due to K. Ding yields Schubert varieties from Ferrers boards. The poset structure of the Schubert cells in these varieties is equal to the poset of maximal rook placements on the Ferrers board under the Bruhat order. We determine when two Ferrers boards have isomorphic rook posets. Equivalently, we give an exact categorization of when two Ding Schubert varieties have iden...
متن کاملBijections on m-level rook placements
Suppose the rows of a board are partitioned into sets of m rows called levels. An m-level rook placement is a subset of the board where no two squares are in the same column or the same level. We construct explicit bijections to prove three theorems about such placements. We start with two bijections between Ferrers boards having the same number of m-level rook placements. The first generalizes...
متن کاملAugmented Rook Boards and General Product Formulas
There are a number of so-called factorization theorems for rook polynomials that have appeared in the literature. For example, Goldman, Joichi and White [6] showed that for any Ferrers board B = F (b1, b2, . . . , bn), n
متن کاملRooks on Ferrers Boards and Matrix Integrals
Let C(n; N) = R H N tr Z 2n (dZ) denote a matrix integral by a U(N)-invariant gaussian measure on the space H N of hermitian N N matrices. The integral is known to be always a positive integer. We derive a simple combinatorial interpretation of this integral in terms of rook conngurations on Ferrers boards. The formula C(n; N) = (2n ? 1)!! n X k=0 N k + 1 n k 2 k found by J. Harer and D. Zagier...
متن کاملClassification of Ding’s Schubert Varieties: Finer Rook Equivalence
K. Ding studied a class of Schubert varieties Xλ in type A partial flag manifolds, indexed by integer partitions λ and in bijection with dominant permutations. He observed that the Schubert cell structure of Xλ is indexed by maximal rook placements on the Ferrers board Bλ, and that the integral cohomology groups H∗(Xλ; Z), H ∗(Xμ; Z) are additively isomorphic exactly when the Ferrers boards Bλ,...
متن کامل