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Browsing Algebra and Discrete Mathematics. - № 1 (27). - 2019 by Issue Date

Browsing Algebra and Discrete Mathematics. - № 1 (27). - 2019 by Issue Date

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  • Representations of ordered doppelsemigroups by binary relations 
    Zhuchok, Yu .V.; Koppitz, J. (2019)
    We extend the study of doppelsemigroups and introduce the notion of an ordered doppelsemigroup. We construct the ordered doppelsemigroup of binary relations on an arbitrary set and prove that every ordered doppelsemigroup ...
  • Gram matrices and Stirling numbers of a class of diagram algebras 
    B i, N . K.; Parvathi, M . (2019)
    In this paper, we introduce Gram matrices for the signed partition algebras, the algebra of Z2-relations and the par- tition algebras. The nondegeneracy and symmetic nature of these Gram matrices are establised. ...
  • On certain families of sparse numerical semigroups with Frobenius number even 
    Tizziotti, G.; Villanueva, j. (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
    This paper is about sparse numerical semigroups and applications in the Weierstrass semigroups theory. We describe and find the genus of certain families of sparse numerical semigroups with Frobenius number even and we ...
  • A Ramsey algebraic study of matrices 
    Teoh, Z .Y.; Teh, W.C. (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
    The notion of a topological Ramsey space was introduced by Carlson some 30 years ago. Studying the topological Ramsey space of variable words, Carlson was able to derive many classical combinatorial results in a unifying ...
  • Conjugacy in finite state wreath powers of finite permutation groups 
    liynyk, A . O; Russyev, A . (2019)
    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.
  • On hereditary reducibility of 2-monomial matrices over commutative rings 
    Bondarenko, V. M.; Gildea, J.; Tylyshchak, A. A.; Yurchenko, N.V. (2019)
    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 ...
  • The lattice of quasivarietes of modules over a Dedekind ring 
    Jedlička, P.; Matczak, K .; Mućka, A . (2019)
    In 1995 D. V. Belkin described the lattice of quasivarieties of modules over principal ideal domains [1]. The following paper provides a description of the lattice of subquasivarieties of the variety of modules over a given ...
  • On the Fitting ideals of a multiplication module 
    Hadjirezaei, S.; Karimzadeh, S. (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
    In this paper, we characterize all finitely gene- rated multiplication R-modules whose the first nonzero Fitting ideal of them is contained in only finitely many maximal ideals. Also, we prove that a finitely generated ...
  • On indices and eigenvectors of quivers 
    Dudchenko, I .; lakhotnyk, M.P. (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
    We study formulas for eigenvectors of strongly connected simply laced quivers in terms of eigenvalues. The relation of these formulas to the isomorphism of quivers is investigated.
  • On free vector balleans 
    Protasov, I.; Protasova, K. (ДЗ "ЛНУ імені Тараса Шевченка", 2019)
    A vector balleans is a vector space over R en- dowed with a coarse structure in such a way that the vector opera- tions are coarse mappings. We prove that, for every ballean (X, E), there exists the unique free vector ...
  • Generalized classes of suborbital graphs for the congruence subgroups of the modular group 
    Jaipong, P.; Tapanyo, W. (2019)
    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 ...
  • Classification of homogeneous Fourier matrices Gurmail Singh 
    Singh, G. (2019)
    Modular data are commonly studied in mathe- matics and physics. A modular datum defines a finite-dimensional representation of the modular group SL2(Z). In this paper, we show that there is a one-to-one correspondence ...
  • On the number of topologies on a finite set 
    Kizmaz, M. Y. (2019)
    We denote the number of distinct topologies which can be defined on a set X with n elements by T(n). Similarly, T0(n) denotes the number of distinct T0 topologies on the set X. In the present paper, we prove that for ...
  • Planarity of a spanning subgraph of the intersection graph of ideals of a commutative ring II, Quasilocal Case 
    Vadhel, P.; Visweswaran, S. (2019)
    The rings we consider in this article are com- mutative with identity 1 6= 0 and are not fields. Let R be a ring. We denote the collection of all proper ideals of R by I(R) and the collection I(R) \ {(0)} by I(R) ∗ . ...

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