A Trace Formula For Foliated Flows (Working Paper), 2017 Universidade de Santiago de Compostela

#### A Trace Formula For Foliated Flows (Working Paper), Jesús A. Álvarez López, Yuri A. Kordyukov, Eric Leichtnam

*Summer Conference on Topology and Its Applications*

The talk, based on work in progress, will be about our progress to show a trace formula for foliated flows on foliated spaces, which has been conjectured by V. Guillemin, and later by C. Deninger with more generality. It describes certain Leftchetz distribution of the foliated flow, acting on some version of the leafwise cohomology, in terms of local data at the closed orbits and fixed points.

The Isbell-Hull Of An Asymmetrically Normed Space, 2017 North-West University (South Africa)

#### The Isbell-Hull Of An Asymmetrically Normed Space, Olivier Olela Otafudu, Jurie Conradie, Hans-Peter Künzi

*Summer Conference on Topology and Its Applications*

In this talk, we discuss an explicit method to define the linear structure of the Isbell-hull of an asymmetrically normed space.

Properties Of Weak Domain Representable Spaces, 2017 University of Dayton

#### Properties Of Weak Domain Representable Spaces, Joe Mashburn

*Summer Conference on Topology and Its Applications*

We will explore some of the basic properties of weak domain representable (wdr) spaces, including hereditary properties and properties of products. In particular, we will construct a Baire space that is not wdr, show that products of wdr spaces are wdr, and demonstrate that the factors of a product that is wdr need not themselves be wdr. We will also show that if X is a wdr space and Y ⊆ X such that |Y|=|X| then Y is wdr. We can declare a subset of a wdr space X to be open or to consist of isolated points without losing …

Some Applications Of The Point-Open Subbase Game, 2017 Universidad Autonoma Metropolitana - Iztapalapa

#### Some Applications Of The Point-Open Subbase Game, David Guerrero Sanchez

*Summer Conference on Topology and Its Applications*

Given a subbase S of a space X, the game PO(S,X) is defined for two players P and O who respectively pick, at the n-th move, a point xn 2 X and a set Un 2 S such that xn 2 Un . The game stops after the moves {xn, Un : n 2 !} have been made and the player P wins if the union of the Un’s equals X; otherwise O is the winner. Since PO(S,X) is an evident modification of the well-known point-open game PO(X), the primary line of research is to describe the relationship between PO(X) …

Revelation Of Nano Topology In Cech Rough Closure Spaces, 2017 Madurai Kamaraj University

#### Revelation Of Nano Topology In Cech Rough Closure Spaces, V. Antonysamy, Llellis Thivagar, Arockia Dasan

*Summer Conference on Topology and Its Applications*

The concept of Cech closure space was initiated and developed by E. Cech in 1966. Henceforth many more research scholars set their minds in this theory and developed it to a new height. Pawlak.Z derived and gave shape to Rough set theory in terms of approximation using equivalence relation known as indiscernibility relation. Further Lellis Thivagar enhanced rough set theory into a topology, called Nano Topology, which has at most five elements in it and he also extended this into multi granular nano topology. The purpose of this paper is to derive Nano topology in terms of Cech rough closure …

Rigidity And Nonrigidity Of Corona Algebras, 2017 Miami University - Oxford

#### Rigidity And Nonrigidity Of Corona Algebras, Paul Mckenney, Alessandro Vignati

*Summer Conference on Topology and Its Applications*

Shelah proved in the 1970s that there is a model of ZFC in which every homeomorphism of the Cech-Stone remainder of the natural numbers is induced by a function on the natural numbers. More recently, Farah proved that in essentially the same model, every automorphism of the Calkin algebra on a separable Hilbert space must be induced by a linear operator on the Hilbert space. I will discuss a common generalization of these rigidity results to a certain class of C*-algebras called corona algebras. No prerequisites in C*-algebra will be assumed.

Cohen Reals And The Sequential Order Of Groups, 2017 Tennessee Technological University

#### Cohen Reals And The Sequential Order Of Groups, Alexander Shibakov

*Summer Conference on Topology and Its Applications*

We show that adding uncountably many Cohen reals to a model of diamond results in a model with no countable sequential group with an intermediate sequential order. The same model has an uncountable group of sequential order 2. We also discuss related questions.

Disjoint Infinity Borel Functions, 2017 University of Denver

#### Disjoint Infinity Borel Functions, Daniel Hathaway

*Summer Conference on Topology and Its Applications*

Consider the statement that every uncountable set of reals can be surjected onto R by a Borel function. This is implied by the statement that every uncountable set of reals has a perfect subset. It is also implied by a new statement D which we will discuss: for each real a there is a Borel function f_{a} : RtoR and for each function g : RtoR there is a countable set G(g) of reals such that the following is true: for each a in R and for each function g : R to R, if f_{a} is disjoint …

On The Chogoshvili Homology Theory Of Continuous Maps Of Compact Spaces, 2017 Batumi Shota Rustaveli State University

#### On The Chogoshvili Homology Theory Of Continuous Maps Of Compact Spaces, Anzor Beridze, Vladimer Baladze

*Summer Conference on Topology and Its Applications*

In this paper an exact homology functor from the category **Mor**_{C} of continuous maps of compact Hausdorff spaces to the category **LES** of long exact sequences of abelian groups is defined (cf. [2], [3], [5]). This functor is an extension of the Hu homology theory, which is uniquely defined on the category of continuous maps of finite CW complexes and is constructed without the relative homology groups [9]. To define the given homology functor we use the Chogoshvili construction of projective homology theory [7], [8]. For each continuous map f:X → Y of compact spaces, using the notion of …

Spaces With No S Or L Subspaces, 2017 University of Wisconsin-Oshkosh

#### Spaces With No S Or L Subspaces, Joan Hart, Kenneth Kunen

*Summer Conference on Topology and Its Applications*

We show it consistent for spaces X and Y to be both HS and HL even though their product X ×Y contains an S-space. Recall that an S-space is a T_{3} space that is HS but not HL.

More generally, consider spaces that contain neither an S-space nor an L-space. We say a space is ESLC iff each of its subspaces is either both HS and HL or neither HS nor HL. The "C" in "ESLC" refers to HC; a space is HC iff each of its subspaces has the ccc (countable chain condition) (iff the space has no …

On Continua With Regular Non-Abelian Self Covers, 2017 Bradley University

#### On Continua With Regular Non-Abelian Self Covers, Mathew Timm

*Summer Conference on Topology and Its Applications*

We look at a planar 2-dimensional continuum X which satisfy the following:

Given any finite group G there is an |G|-fold regular self cover f:X → X with G as its group of deck transformations.

Locally Compact Groups: Traditions And Trends, 2017 Technische Universitat Darmstadt

#### Locally Compact Groups: Traditions And Trends, Karl Heinrich Hofmann, Wolfgang Herfort, Francesco G. Russo

*Summer Conference on Topology and Its Applications*

For a lecture in the Topology+Algebra and Analysis section, the subject of locally compact groups appears particularly fitting: Historically and currently as well, the structure and representation theory of locally compact groups draws its methods from each of theses three fields of mathematics. Nowadays one might justifiably add combinatorics and number theory as sources. The example of a study of a class of locally compact groups called “near abelian,” undertaken by W. Herfort, K. H. Hofmann, and F. G. Russo, may be used to illustrate the liaison of topological group theory with this different areas of interest. Concepts like the …

Lifting Homeomorphisms Of Cyclic Branched Covers Of The Sphere, 2017 University of Wisconsin - Milwaukee

#### Lifting Homeomorphisms Of Cyclic Branched Covers Of The Sphere, Rebecca R. Winarski, Tyrone Ghaswala

*Summer Conference on Topology and Its Applications*

Birman and Hilden ask: given finite branched cover X over the 2-sphere, does every homeomorphism of the sphere lift to a homeomorphism of X? For covers of degree 2, the answer is yes, but the answer is sometimes yes and sometimes no for higher degree covers. In joint work with Ghaswala, we completely answer the question for cyclic branched covers. When the answer is yes, there is an embedding of the mapping class group of the sphere into a finite quotient of the mapping class group of X. In a family where the answer is no, we find a presentation …

Braid Group Actions On Rational Maps, 2017 American Mathematical Society

#### Braid Group Actions On Rational Maps, Eriko Hironaka, Sarah Koch

*Summer Conference on Topology and Its Applications*

Rational maps are maps from the Riemann sphere to itself that are defined by ratios of polynomials. A special type of rational map is the ones where the forward orbit of the critical points is finite. That is, under iteration, the critical points all eventually cycle in some periodic orbit. In the 1980s Thurston proved the surprising result that (except for a well-understood set of exceptions) when the post-critical set is finite the rational map is determined by the “combinatorics” of how the map behaves on the post-critical set. Recently, there has been interest in the question: what happens if …

Compactly Supported Homeomorphisms As Long Direct Limits, 2017 Technische Universitat Darmstadt

#### Compactly Supported Homeomorphisms As Long Direct Limits, Rafael Dahmen, Gábor Lukács

*Summer Conference on Topology and Its Applications*

Let λ be a limit ordinal and consider a directed system of topological groups (G_{α})_{α < λ} with topological embeddings as bonding maps and its directed union G=∪_{α < λ}G_{α}. There are two natural topologies on G: one that makes G the direct limit (colimit) in the category of topological spaces and one which makes G the direct limit (colimit) in the category of topological groups.

For λ = ω it is known that these topologies almost never coincide (*Yamasaki's Theorem).*

In my talk last year, I introduced the *Long Direct Limit Conjecture*, stating that …

On Roitman's Principle For Box Products, 2017 Universidad Nacional Autonoma de Mexico

#### On Roitman's Principle For Box Products, Hector Alonso Barriga-Acosta

*Summer Conference on Topology and Its Applications*

One of the oldest problems in box products is if the countable box product of the convergent sequence is normal. It is known that consistenly (e.g., b=d, d=c) the answer is affirmative. A recent progress is due to Judy Roitman that states a combinatorial principle which also implies the normality and holds in many models.

Although the countable box product of the convergent sequence is normal in some models of b < d < c, Roitman asked what happen with her principle in this models. We answer that Roitman's principle is true in some models of b < d < c.

Liouville Numbers And One-Sided Ergodic Hilbert Transformations, 2017 Wesleyan University

#### Liouville Numbers And One-Sided Ergodic Hilbert Transformations, David Constantine, Joanna Furno

*Summer Conference on Topology and Its Applications*

We examine one-sided ergodic Hilbert transforms for irrational circle rotations and some mean-zero functions. Our approach uses continued fraction expansions to specify rotations by Liouville numbers for which the transformation has everywhere convergence or divergence.

Entropy In Topological Groups, Part 2, 2017 University of Udine

#### Entropy In Topological Groups, Part 2, Dikran Dikranjan

*Summer Conference on Topology and Its Applications*

Entropy was introduced first in thermodynamics and statistical mechanics, as well as information theory. In the last sixty years entropy made its way also in topology, ergodic theory, as well as other branches of mathematics as algebra, geometry and number theory where dynamical systems appear in one way or another.

Roughly speaking, entropy is a non-negative real number or infinity assigned to a "selfmap" T of a "space" X, where the "space" X can be a topological or uniform space, a measure space, an abstract or topological group (or vector space) or just a set. The "selfmap" T can be, …

On Product Stability Of Asymptotic Property C, 2017 University of North Carolina at Greensboro

#### On Product Stability Of Asymptotic Property C, Gregory C. Bell, Andrzej Nagórko

*Summer Conference on Topology and Its Applications*

Asymptotic property C is a dimension-like large-scale invariant of metric spaces that is of interest when applied to spaces with infinite asymptotic dimension. It was first described by Dranishnikov, who based it on Haver's topological property C. Topological property C fails to be preserved by products in very striking ways and so a natural question that remained open for some 10+ years is whether asymptotic property C is preserved by products. Using a technique inspired by Rohm we show that asymptotic property C is preserved by direct products of metric spaces.

Sequential Order Of Compact Scattered Spaces, 2017 University of North Carolina at Charlotte

#### Sequential Order Of Compact Scattered Spaces, Alan Dow

*Summer Conference on Topology and Its Applications*

A space is sequential if the closure of set can be obtained by iteratively adding limits of converging sequences. The sequential order of a space is a measure of how many iterations are required. A space is scattered if every non-empty set has a relative isolated point. It is not known if it is consistent that there is a countable (or finite) upper bound on the sequential order of a compact sequential space. We consider the properties of compact scattered spaces with infinite sequential order.