A doubly stochastic matrix is a square matrix A = (aij ) of non-negative real numbers such that P i aij = P j aij = 1. The Chebyshev polynomial of the first kind is defined by the recur- rence relation T0(x) = ...

Let R and R′ be alternative rings. In this article we investigate the additivity of surjective elementary maps of R × R′ . As a main theorem, we prove that if R contains a non-trivial idempotent satisfying some conditions, ...

In this paper we prove that the group (Zp) 2 × Zq ×Zr is CI-group, where p, q, r are primes such that q and r divide p − 1, and r divides q − 1.

We accomplish the classification of Cohen–Macaulay modules over the curve singularities of type T44 and the description of the corresponding matrix factorizations, started in.

It is proved that conjugated periodic elements of the infinite wreath power of a finite permutation group are conjugated in the finite state wreath power of this group. Counterexamples for nonperiodic elements are given.

Let Γ be the modular group. We extend a non-trivial Γ-invariant equivalence relation on Qb to a general relation by replacing the group Γ0(n) by ΓK(n), and determine the suborbital graph F K u,n, an extended concept of ...

In this paper, we introduce the notion of globalization for partial module coalgebra and for partial comodule coalgebra. We show that every partial module coalgebra is globalizable exhibiting a standard globalization. We ...

The set of distinct eigenvalues of a signed digraph S together with their respective multiplicities is called its spectrum. Two signed digraphs of same order are said to be cospectral if they have the same spectrum. In ...

A 2-monomial matrix over a commutative ring R is by definition any matrix of the form M(t, k, n) = Φ Ik 0 0 tIn−k , 0 < k < n, where t is a non-invertible element of R, Φ the companion matrix to λ n − 1 and Ik ...