For a nonnegative n× n matrix A, we find that there is a polynomial f(x) ∈ R[x] such that f(A) is a positive matrix of rank one if and only if A is irreducible. Furthermore, we show that the lowest degree such polynomial f(x) with tr f(A) = n is unique. Thus, generalizing the well-known definition of the Hoffman polynomial of a strongly connected regular digraph, for any irreducible nonnegative...

An explicit character formula is established for any strongly generic finite-dimensional irreducible g-module, g being an arbitrary finite-dimensional complex Lie superalgebra. This character formula had been conjectured earlier by Vera Serganova and the author for any generic irreducible finite-dimensional g-module, i.e. such that its highest weight is far enough from the walls of the Weyl cha...

Let T be a compressible torus in an irreducible 3-manifold M other than S. It is easy to see that either : 1. T bounds a solid torus, or: 2. T bounds a submanifold homeomorphic to the exterior of a non-trivial knot in S, where the compressing disk for T is a meridian disk of the knot. The intersection of a strongly irreducible Heegaard surface with solid tori was analyzed by Y.Moriah and H.Rubi...

Let G be a residually finite group and let A be a finite set. We prove that if X ⊂ A is a strongly irreducible subshift of finite type containing a periodic configuration then periodic configurations are dense in X. The density of periodic configurations implies in particular that every injective endomorphism of X is surjective and that the group of automorphisms of X is residually finite. We a...

In this paper we present a combinatorial study of binomial ideals of dimension 1 of k[X1, . . . , Xn], using monomial parametrizations of the irreducible affine curves defined by their associated primes. We find an algorithm that checks whether or not the ideal of a union of monomial curves is binomial and another one that calculates curves such that their associated ideal is a prescribed latti...

Let V be a vector space over a fully ordered field F. In Sec. 2 we characterize cones K with ascending chain condition (ACC) on faces of Ii. In Sec. 3 we show that if K has ACC on faces, then an operator A is strongly irreducible if and only if A is irreducible. In Sec. 4 we prove theorems of Perron-Frobenius type for a strongly irreducible operator A in the case that FR, the real field, and K ...