Order theory | Closure operators | Properties of topological spaces
In topology, an Alexandrov topology is a topology in which the intersection of any family of open sets is open. It is an axiom of topology that the intersection of any finite family of open sets is open; in Alexandrov topologies the finite restriction is dropped. A set together with an Alexandrov topology is known as an Alexandrov-discrete space or finitely generated space. Alexandrov topologies are uniquely determined by their specialization preorders. Indeed, given any preorder ≤ on a set X, there is a unique Alexandrov topology on X for which the specialization preorder is ≤. The open sets are just the upper sets with respect to ≤. Thus, Alexandrov topologies on X are in one-to-one correspondence with preorders on X. Alexandrov-discrete spaces are also called finitely generated spaces since their topology is uniquely determined by the family of all finite subspaces. Alexandrov-discrete spaces can thus be viewed as a generalization of finite topological spaces. Due to the fact that inverse images commute with arbitrary unions and intersections, the property of being an Alexandrov-discrete space is preserved under quotients. Alexandrov-discrete spaces are named after the Russian topologist Pavel Alexandrov. They should not be confused with the more geometrical Alexandrov spaces introduced by the Russian mathematician Aleksandr Danilovich Aleksandrov. (Wikipedia).
Topology (What is a Topology?)
What is a Topology? Here is an introduction to one of the main areas in mathematics - Topology. #topology Some of the links below are affiliate links. As an Amazon Associate I earn from qualifying purchases. If you purchase through these links, it won't cost you any additional cash, b
From playlist Topology
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From playlist Topology
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Topic: Symplectic topology and the loop space Speaker: Jingyu Zhao, Member, School of Mathematics Time/Room: 4:45pm - 5:00pm/S-101 More videos on http://video.ias.edu
From playlist Mathematics
Algebraic topology: Introduction
This lecture is part of an online course on algebraic topology. This is an introductory lecture, where we give a quick overview of some of the invariants of algebraic topology (homotopy groups, homology groups, K theory, and cobordism). The book "algebraic topology" by Allen Hatcher men
From playlist Algebraic topology
François Petit (6/22/20): Ephemeral persistence modules and distance comparison
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From playlist ATMCS/AATRN 2020
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Fernando Galaz Garcia: Three dimensional Alexandrov spaces with positive and non negative curvature
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From playlist HIM Lectures: Follow-up Workshop to JTP "Optimal Transportation"
Lecture 17: Alexandrov's Theorem
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From playlist MIT 6.849 Geometric Folding Algorithms, Fall 2012
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From playlist Topology
Analytic Geometry Over F_1 - Vladimir Berkovich
Vladimir Berkovich Weizmann Institute of Science March 10, 2011 I'll talk on work in progress on algebraic and analytic geometry over the field of one element F_1. This work originates in non-Archimedean analytic geometry as a result of a search for appropriate framework for so called skel
From playlist Mathematics
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From playlist MIT 6.849 Geometric Folding Algorithms, Fall 2012
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From playlist Algebraic Topology
A topological view on the Monge-Ampere equation without convexity assumptions - Jonas Hirsch
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From playlist Mathematics
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From playlist Bridging Applied and Quantitative Topology 2022
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From playlist Beyond TDA - Persistent functions and its applications in data sciences, 2021
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From playlist Summer School 2020: Motivic, Equivariant and Non-commutative Homotopy Theory
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From playlist OUTREACH - GRAND PUBLIC
Nekrashevych: Constructing simple groups using dynamical systems
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From playlist Topology