Scientific Seminar
at Geometry and Topology Department of
Ivan Franko National University of Lviv
Archive for (2019/2020) academic year



Topological
Algebra

September 4, 2019 S. Bardyla
(Kurt Gödel Research Center, University of Vienna)
  • Recent progress in the theory of complete (semi)topological semilattices

    We shall discuss recent results on complete semitopological semilattices and an interplay between completeness and absolute H-closedness. Some open problems will be posed.

September 25, 2019 T. Banakh
  • Geometry Multiverse

    We survey the functorial dependence between various geometry categories: topology, uniform topology, asymptology, bornologies, function algebras, compactifications, group algebras.

October 2, 2019 М. Михаленич
  • Схеми Вороного

    Розглядаються розширення динамічних схем Вороного. Наведено авлгоритми та приклади у випадку n=4.

October 16, 2019 T. Mokrytskyi
  • Topological coding and topological matrices toward network overall security

    We discuss on the results of the paper: Bing Yao, Meimei Zhao, Xiaohui Zhang, Yarong Mu, Yirong Sun, Mingjun Zhang, Sihua Yang, Fei Ma, Jing Su, Xiaomin Wang, Hongyu Wang, Hui Sun, Topological coding and topological matrices toward network overall security, arXiv:1909.01587.

October 23, 2019 T. Mokrytskyi
  • Topological coding and topological matrices toward network overall security, II

    We discuss on the results of the paper: Bing Yao, Meimei Zhao, Xiaohui Zhang, Yarong Mu, Yirong Sun, Mingjun Zhang, Sihua Yang, Fei Ma, Jing Su, Xiaomin Wang, Hongyu Wang, Hui Sun, Topological coding and topological matrices toward network overall security, arXiv:1909.01587.

October 30, 2019 T. Mokrytskyi
  • Topological coding and topological matrices toward network overall security, III

    We discuss on the results of the paper: Bing Yao, Meimei Zhao, Xiaohui Zhang, Yarong Mu, Yirong Sun, Mingjun Zhang, Sihua Yang, Fei Ma, Jing Su, Xiaomin Wang, Hongyu Wang, Hui Sun, Topological coding and topological matrices toward network overall security, arXiv:1909.01587.

November 4, 2019 P. Khylynskyi
  • The semilattice of topologies on an infinite semigroup of matrix units

    We discuss on structure of the semilattice of topologies on an infinite semigroup of $\lambda\times\lambda$-matrix units $B_\lambda$. In particular minimal semigroup topologies on $B_\lambda$ will be described.

November 27, 2019 P. Khylynskyi
  • The semilattice of topologies on an infinite semigroup of matrix units, II

    We discuss on structure of the semilattice of topologies on an infinite semigroup of $\lambda\times\lambda$-matrix units $B_\lambda$. In particular minimal semigroup topologies on $B_\lambda$ will be described.

January 3, 2020 S. Bardyla
(Kurt Gödel Research Center, University of Vienna)
  • On regular $\kappa$-bounded spaces admitting only constant continuous mappings into $T_1$ spaces of pseudo-character $\leq \kappa$

    For each cardinal $\kappa$ we construct an infinite $\kappa$-bounded (and hence countably compact) regular space $R_{\kappa}$ such that for any $T_1$ space $Y$ of pseudo-character $\leq\kappa$, each continuous function $f:R_{\kappa}\rightarrow Y$ is constant. This result resolves two problems posted by Tzannes in Open Problems from Topology Proceedings [E. Pearl, Problems from Topology Proceedings, Topology Atlas, Toronto, 2003] and extends results of Ciesielski and Wojciechowski [K.C. Ciesielski and J. Wojciechowski, Cardinality of regular spaces admitting only constant continuous functions, Topology Proceedings, 47 (2016), 313-329.] and Herrlich [H. Herrlich, Wann sind alle stetigen, Abbildungen in $Y$ Konstant? Math. Z. 90 (1965), 152-154].
    This is joint work with Alexander Osipov.

January 10, 2020 S. Bardyla
(Kurt Gödel Research Center, University of Vienna)
  • On regular $\kappa$-bounded spaces admitting only constant continuous mappings into $T_1$ spaces of pseudo-character $\leq \kappa$, II

    For each cardinal $\kappa$ we construct an infinite $\kappa$-bounded (and hence countably compact) regular space $R_{\kappa}$ such that for any $T_1$ space $Y$ of pseudo-character $\leq\kappa$, each continuous function $f:R_{\kappa}\rightarrow Y$ is constant. This result resolves two problems posted by Tzannes in Open Problems from Topology Proceedings [E. Pearl, Problems from Topology Proceedings, Topology Atlas, Toronto, 2003] and extends results of Ciesielski and Wojciechowski [K.C. Ciesielski and J. Wojciechowski, Cardinality of regular spaces admitting only constant continuous functions, Topology Proceedings, 47 (2016), 313-329.] and Herrlich [H. Herrlich, Wann sind alle stetigen, Abbildungen in $Y$ Konstant? Math. Z. 90 (1965), 152-154].
    This is joint work with Alexander Osipov.

February 19, 2020 P. Khylynskyi
  • The minimal semigroup topologies on an infinite semigroup of matrix units, II

    We discuss on structure of the semilattice of topologies on an infinite semigroup of matrix units. Also, minimal semigroup topologies on such semigroups will be partially described.
    This is a continuation of the report on the seminar Topology & Applications

March 11, 2020 O. Gutik
Video:
May 22, 2020 P. Khylynskyi
  • Minimal topologies on semigroup of matrix units

    We discuss on structure of the semilattice of topologies on semigroup of matrix units. In particular, we describe all minimal topologies in some class of semigroup topologies on semigroup of matrix units.