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We study Polish spaces for which a set of possible distances $A \subseteq \mathbb{R}^+$ is fixed in advance. We determine, depending on the properties of $A$, the complexity of the collection of all Polish metric spaces with distances in…

Logic · Mathematics 2020-06-30 Riccardo Camerlo , Alberto Marcone , Luca Motto Ros

The well known ideal presentations of countably based domains were recently extended to (effective) quasi-Polish spaces. Continuing these investigations, we explore some classes of effective quasi-Polish spaces. In particular, we prove an…

Logic · Mathematics 2023-01-23 Matthew de Brecht , Takayuki Kihara , Victor Selivanov

We investigate the effectivizations of several equivalent definitions of quasi-Polish spaces and study which characterizations hold effectively. Being a computable effectively open image of the Baire space is a robust notion that admits…

Logic · Mathematics 2019-05-08 Mathieu Hoyrup , Cristobal Rojas , Victor Selivanov , Donald M. Stull

Following the work of Friedman, Koerwien, Nies and Schlicht we positively answer their question whether the Scott rank of Polish metric spaces is countable.

Logic · Mathematics 2018-02-09 Michal Doucha

We introduce the notion of compactifiable classes -- these are classes of metrizable compact spaces that can be up to homeomorphic copies ``disjointly combined'' into one metrizable compact space. This is witnessed by so-called compact…

General Topology · Mathematics 2020-02-19 A. Bartoš , J. Bobok , J. van Mill , P. Pyrih , B. Vejnar

We propose and study a new approach to the topologization of spaces of (possibly not all) future-directed causal curves in a stably causal spacetime. It relies on parametrizing the curves "in accordance" with a chosen time function. Thus…

Mathematical Physics · Physics 2018-03-09 Tomasz Miller

We analyse logic actions of Polish groups which arise in continuous logic. We extend the generalised model theory of H.Becker to the case of Polish G-spaces when G is an arbitrary Polish group.

Logic · Mathematics 2015-11-02 Aleksander Ivanov , Barbara Majcher-Iwanow

We show some basic results on the characterization of quasi-Polish spaces in terms of spaces of ideals, with an emphasis on the connections with computable topology.

Logic · Mathematics 2020-04-29 Matthew de Brecht

We characterize coset spaces of topological groups which are coset spaces of (separable) metrizable groups and complete metrizable (Polish) groups. Besides, it is shown that for a $G$-space $X$ with a $d$-open action there is a topological…

General Topology · Mathematics 2017-11-29 Sergey Antonyan , Natella Antonyan , Konstantin Kozlov

We study the usual notion of Scott rank but in the setting of Polish metric spaces. The signature consists of distance relations: for each rational $q > 0$, there is a relation $R_{<q}(x,y)$ stating that the distance of $x$ and $y $ is less…

Metric Geometry · Mathematics 2019-06-04 Sy Friedman , Katia Fokina , Martin Koerwien , Andre Nies

We investigate computable metrizability of Polish spaces up to homeomorphism. In this paper we focus on Stone spaces. We use Stone duality to construct the first known example of a computable topological Polish space not homeomorphic to any…

Logic · Mathematics 2023-11-08 Nikolay Bazhenov , Matthew Harrison-Trainor , Alexander Melnikov

We use Fra\" iss\'e theoretic methods to construct several universal and ultrahomogeneous Polish metric structures. Namely, universal and ultrahomogeneous Polish metric space equipped with countably many closed subsets of its powers,…

Logic · Mathematics 2013-05-03 Michal Doucha

We show that a set of non-negative reals is the distance set of a separable complete metric space if and only if it is either countable or is an analytic set which has 0 as a limit point. We also consider spaces with simpler distance sets.

Logic · Mathematics 2025-09-03 John D. Clemens

A topological space is almost locally compact if it contains a dense locally compact subspace. We generalize a result from \cite{Ma}, showing that isomorphism on Borel classes of almost locally compact Polish metric structures is always…

Logic · Mathematics 2025-08-12 Maciej Malicki

We analyze the effective content of countable, second countable topological spaces by directly calculating the complexity of several topologically defined index sets. We focus on the separation principles, calibrating an arithmetic…

Logic · Mathematics 2025-07-25 Andrew DeLapo , David Gonzalez

We will characterise robust monetary utility functions defined on the space of real valued (bounded) continuous functions on a Polish space.

Probability · Mathematics 2022-09-20 Freddy Delbaen

We show a necessary and sufficient condition for any ordinal number to be a Polish space. We also prove that for each countable Polish space, there exists a countable ordinal number that is an upper bound for the first component of the…

General Mathematics · Mathematics 2024-04-12 Borys Álvarez-Samaniego , Andrés Merino

In this article we extend the notion of metric measure spaces to so-called metric two-level measure spaces (m2m spaces): An m2m space $(X, r, \nu)$ is a Polish metric space $(X, r)$ equipped with a two-level measure $\nu \in…

Probability · Mathematics 2020-04-30 Roland Meizis

We will see how to define the metric $\beta$, which turns the topological space of continuous functions whose domains are open subsets of a locally compact and second countable space $X$ to values in a polish space $Y$, called…

General Topology · Mathematics 2026-02-11 Edwar Alexis Ramírez Ardila

Building on our prior work on axiomatization of exact real computation by formalizing nondeterministic first-order partial computations over real and complex numbers in a constructive dependent type theory, we present a framework for…

Logic in Computer Science · Computer Science 2024-10-18 Michal Konečný , Sewon Park , Holger Thies
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