Digital Repository of Luhansk Taras Shevchenko National University

# Browsing Algebra and Discrete Mathematics. - № 2 (27). - 2019 by Issue Date

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• (2019)
A family L of subsets of a set X is called linked if A ∩ B 6= ∅ for any A, B ∈ L. A linked family M of subsets of X is maximal linked if M coincides with each linked family L on X that contains M. The superextension ...
• (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
We investigate the row and column structure of solutions of the matrix polynomial equation A(λ)X(λ) + Y (λ)B(λ) = C(λ), where A(λ), B(λ) and C(λ) are the matrices over the ring of poly- nomials F[λ] with coefficients ...
• (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
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 ...
• (2019)
In this paper, R is a finite chain ring of invariants (q, s), and l is a positive integer fulfilling gcd(l, q) = 1. In the language of q-cyclotomic cosets modulo l, the cyclic codes over R of length l are uniquely decomposed ...
• (2019)
Using (introduced by the first author) the method of (min, max)-equivalence, we classify all serial principal posets, i.e. the posets S satisfying the following conditions: (1) the quadratic Tits form qS(z) : Z |S|+1 ...
• (2019)
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) = ...
• (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
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 ...
• (2019)
The first step in the study of all types of algebras is the description of such algebras having small dimensions. The structure of 3-dimensional Leibniz algebras is more complicated than 1 and 2-dimensional cases. In this ...
• (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
Let p, q > 2 be relatively prime integers and let Hp,q be the generalized Hecke group associated to p and q. The generalized Hecke group Hp,q is generated by X(z) = −(z − λp)−1 and Y (z) = −(z + λq) −1 where λp = 2 cos ...
• (2019)
Let (P, 6) be an atomic partially ordered set (poset, briefly) with a minimum element 0 and I(P) the set of nontrivial ideals of P. The inclusion ideal graph of P, denoted by Ω(P), is an undirected and simple graph with ...