Scientific Seminar
at Algebra & Logic and Geometry & Topology Departments of
Ivan Franko National University of Lviv
Archive for (2015/2016) academic year

S-acts Theory and
Spectral Spaces

September 15, 2015 O. Gutik
  • Divertisement
    • Active participants of the seminar will present and discuss interesting open problems from various branches of the theory of semigroups and their acts.
November 3, 2015 O. Gutik
  • On the semigroup of co-finite oriented partial homeomorphisms of the real line
    • We discuss on the results obtained by the reporter and his colleagues on this topic.
November 10, 2015 Т. Мокрицький
  • Структура інверсних напівгруп графів
    • Обговорюються результати, отримані в праці: Zachary Mesyan, J. D. Mitchell, The Structure of a Graph Inverse Semigroup (arXiv:1409.4380).
November 17, 2015 Т. Мокрицький
  • Структура інверсних напівгруп графів, II
    • Обговорюються результати, отримані в праці: Zachary Mesyan, J. D. Mitchell, The Structure of a Graph Inverse Semigroup (arXiv:1409.4380).
November 24, 2015 Т. Мокрицький
  • Структура інверсних напівгруп графів, III
    • Обговорюються результати, отримані в праці: Zachary Mesyan, J. D. Mitchell, The Structure of a Graph Inverse Semigroup (arXiv:1409.4380).
February 16, 2016 O. Gutik
  • On the monoid of monotone injective partial selfmaps of ℕ2≤ with cofinite domains and images
    • Let ℕ2≤ be the set ℕ2 with the partial order defining as a product of usual order ≤ on the set of positive integers ℕ. We discuss on algebraic property of the semigroup PO∞(ℕ2≤) of monotone injective partial selfmaps of ℕ2≤ having cofinite domain and image and post some problems on this topics.
March 22, 2016 A. Ravsky
  • Straight-line crossing-free graph drawings on minimal number of lines or planes
    • As a graph we understand a finite simple graph (that is, an undirected graph without multiple edges and loops). As a drawing of a graph we understand a straight-line crossing-free drawing, that is, such a drawing in which edges of the graph are represented by mutually non-crossing segments of straight lines. It is easy to show that each graph can be drawn in space. Moreover, by Wagner-Fáry-Stein Theorem, each planar graph can be drawn in plane. We present some results about minimal number of lines or planes needed to draw graphs (from different classes) in a plane or in space.
March 29, 2016 A. Ravsky
  • Straight-line crossing-free graph drawings on minimal number of lines or planes, II
    • As a graph we understand a finite simple graph (that is, an undirected graph without multiple edges and loops). As a drawing of a graph we understand a straight-line crossing-free drawing, that is, such a drawing in which edges of the graph are represented by mutually non-crossing segments of straight lines. It is easy to show that each graph can be drawn in space. Moreover, by Wagner-Fáry-Stein Theorem, each planar graph can be drawn in plane. We present some results about minimal number of lines or planes needed to draw graphs (from different classes) in a plane or in space.
April 5, 2016 A. Ravsky
  • Straight-line crossing-free graph drawings on minimal number of lines or planes, III
    • As a graph we understand a finite simple graph (that is, an undirected graph without multiple edges and loops). As a drawing of a graph we understand a straight-line crossing-free drawing, that is, such a drawing in which edges of the graph are represented by mutually non-crossing segments of straight lines. It is easy to show that each graph can be drawn in space. Moreover, by Wagner-Fáry-Stein Theorem, each planar graph can be drawn in plane. We present some results about minimal number of lines or planes needed to draw graphs (from different classes) in a plane or in space.
April 12, 2016 A. Ravsky
  • Straight-line crossing-free graph drawings on minimal number of lines or planes, IV
    • As a graph we understand a finite simple graph (that is, an undirected graph without multiple edges and loops). As a drawing of a graph we understand a straight-line crossing-free drawing, that is, such a drawing in which edges of the graph are represented by mutually non-crossing segments of straight lines. It is easy to show that each graph can be drawn in space. Moreover, by Wagner-Fáry-Stein Theorem, each planar graph can be drawn in plane. We present some results about minimal number of lines or planes needed to draw graphs (from different classes) in a plane or in space.
May 10, 2016 K. Maksymyk
  • Напівгрупи інтерасоціативні біциклічній напівгрупі
    • Обговорюються результати, отримані в праці: Berit Nilsen Givens, Amber Rosin, Karen Linton, Interassociates of the bicyclic semigroup, Semigroup Forum DOI 10.1007/s00233-016-9794-9
May 17, 2016 K. Maksymyk
  • Напівгрупи інтерасоціативні біциклічній напівгрупі, II
    • Обговорюються результати, отримані в праці: Berit Nilsen Givens, Amber Rosin, Karen Linton, Interassociates of the bicyclic semigroup, Semigroup Forum DOI 10.1007/s00233-016-9794-9
May 24, 2016 K. Maksymyk
  • Напівгрупи інтерасоціативні біциклічній напівгрупі, III
    • Обговорюються результати, отримані в праці: Berit Nilsen Givens, Amber Rosin, Karen Linton, Interassociates of the bicyclic semigroup, Semigroup Forum DOI 10.1007/s00233-016-9794-9
May 31, 2016 K. Maksymyk
  • Напівгрупи інтерасоціативні біциклічній напівгрупі, IV
    • Обговорюються результати, отримані в праці: Berit Nilsen Givens, Amber Rosin, Karen Linton, Interassociates of the bicyclic semigroup, Semigroup Forum DOI 10.1007/s00233-016-9794-9.
August 3, 2016 A. Савчук
August 9, 2016 A. Савчук
August 16, 2016 O. Гутік
August 18, 2016 A. Савчук

| Archive | Home |