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# Topology - Set-Theoretic

**DMS Set Theoretic Topology Seminar**

Jan 16, 2019 02:00 PM

Parker Hall 246 (New Room)

PLEASE NOTE **NEW ROOM 246**

Speaker: **Gary Gruenhage**

Abstract. A space X is said to be Y-selective if every lower semi-continuous mapping F from the space Y to the non-empty closed subsets of X has a continuous selection, i.e., there is a continuous f from Y to X with f(y) in F(y) for each y in Y. X is self-selective if it is X-selective. R. Shen and H.J.K. Junnila asked if the space of ordinals less than or equal to the first uncountable ordinal is self-selective. We show that it is not.

**DMS Set Theoretic Topology Seminar**

Dec 05, 2018 02:00 PM

Parker Hall 328

Speaker: **Ziqin Feng** will continue his talk from 11/14 (and finish, as tomorrow is our last meeting of the semester).

**DMS Set Theoretic Topology Seminar**

Nov 14, 2018 02:00 PM

Parker Hall 328

Speaker:

**Xiqin Feng**

**DMS Set Theoretic Topology Seminar**

Nov 07, 2018 02:00 PM

Parker Hall 328

Mark will continue

Abstract. In 1979, van Douwen and Pfeffer introduced D-spaces and showed every finite power of the Sorgenfrey line is a D-space. Two years later, de Caux proved that every finite power of the Sorgenfrey line is hereditarily a D-space. Peng introduced the notion of transitively D-spaces in 2008, and Dauvergne demonstrated in 2016 that a transitively D-space need not be a D-space. We build on de Caux's technique to show every finite power of a GO-topology on the reals is hereditarily a transitively D-space.

**DMS Set Theoretic Topology Seminar**

Oct 31, 2018 02:00 PM

Parker Hall 328

**Mark** will continue.

Abstract. In 1979, van Douwen and Pfeffer introduced D-spaces and showed every finite power of the Sorgenfrey line is a D-space. Two years later, de Caux proved that every finite power of the Sorgenfrey line is hereditarily a D-space. Peng introduced the notion of transitively D-spaces in 2008, and Dauvergne demonstrated in 2016 that a transitively D-space need not be a D-space. We build on de Caux's technique to show every finite power of a GO-topology on the reals is hereditarily a transitively D-space.

**DMS Set Theoretic Topology Seminar**

Oct 24, 2018 02:00 PM

Parker Hall 328

Speaker: **Mark Guest**

Abstract. In 1979, van Douwen and Pfeffer introduced D-spaces and showed every finite power of the Sorgenfrey line is a D-space. Two years later, de Caux proved that every finite power of the Sorgenfrey line is hereditarily a D-space. Peng introduced the notion of transitively D-spaces in 2008, and Dauvergne demonstrated in 2016 that a transitively D-space need not be a D-space. We build on de Caux's technique to show every finite power of a GO-topology on the reals is hereditarily a transitively D-space.

**DMS Set Theoretic Topology Seminar**

Oct 17, 2018 02:00 PM

Parker Hall 328

**Rongxin**will continue

**DMS Set Theoretic Topology Seminar**

Oct 10, 2018 02:00 PM

Parker Hall 328

Speaker: **Rongxin Shen**

Abstract. This is joint work with Heikki Junnila. The notion of a reflexive family of sets in topological spaces originated in research on the invariant subspace problem in functional analysis. In [Fund. Math., 192 (2006), 111--120], Yang and Zhao introduced the s-reflexive spaces in which reflexive families can be characterized in a simple way. We prove that every s-reflexive Hausdorff space is zero-dimensional, and we indicate a close relationship between the theory of s-reflexive spaces and that of continuous selections. Several examples relating to s-reflexivity are given. Also we will talk about some unsolved problems on this topic.

**DMS Set Theoretic Topology Seminar**

Sep 19, 2018 02:00 PM

Parker Hall 328

**Gary Gruenhage**will continue presenting the paper of Dow and Juhasz.

**DMS Set Theoretic Topology Seminar**

Sep 12, 2018 02:00 PM

Parker Hall 328

**Hongfeng Guo** will show that there is a monotonically monolithic space which has no predictable network under the assumption \(2^{\omega_0}<2^{\omega_1}\).

This is joint work with Ziqin Feng.

Last Updated: 09/11/2015