This is the third part of the five-part saga on the umbral transfermatrix method, based on Gian-Carlo Rota’s seminal notion of the umbra. In this article we describe the Maple package ZOO that for any specific k, automatically constructs an umbral scheme for enumerating “k-board” lattice animals (polyominoes) on the two-dimensional square lattice. Such umbral schemes enable counting these impor...

Recall a counting problem is a function f : Σ∗ 7→ N that maps input (strings) to the number of solutions. For example, in 3-SAT, the input is a CNF formula and the output is the number of satisfying assignments. Almost all interesting counting problems belong to the class #P, which means that there is a polynomial time nondeterministic Turing machine with the property that, for all x, f(x) is t...

The Single Cut or Join (SCJ) operation on genomes, generalizing chromosome evolution by fusions and fissions, is the computationally simplest known model of genome rearrangement. While most genome rearrangement problems are already hard when comparing three genomes, it is possible to compute in polynomial time a most parsimonious SCJ scenario for an arbitrary number of genomes related by a bina...

The polytope model is widely used in compiler analysis for representing a certain class of programs. Many counting problems that occur in the analysis of such programs can be solved by counting the number of integer points in a parametric polytope. In other counting problems, polynomial weights are assigned to the integer points of a parametric polytope and the objective is to find the sum of t...

We provide polynomial-time algorithms for counting the number of perfect matchings and the number of matchings in chain graphs, cochain graphs, and threshold graphs. These algorithms are based on newly developed subdivision schemes that we call a recursive decomposition. On the other hand, we show the #P-completeness for counting the number of perfect matchings in chordal graphs, split graphs a...

We study the polynomial time counting hierarchy, a hierarchy of complexity classes related to the notion of counting. We investigate some of their structural properties, settling many open questions dealing with oracle characterizations, closure under boolean operations, and relations with other complexity classes. We develop a new combinatorial technique to obtain relativized separations for s...

In this article, associated to a (bordered) Legendrian graph, we study and show the equivalence between two isotopy invariants: augmentation number via point-counting over finite field, for variety of Chekanov-Eliashberg differential graded algebra, ruling polynomial combinatorics decompositions front projection.

Recently, Abiteboul and Kanellakis introduced the notion of determinate query to describe database queries having the ability to create new domain elements. As there are no natural determinate-complete query languages known, more restrictive (the constructive queries) and more general (the semi-deterministic queries) notions of query were considered. Here, we show that the advantage of the seco...