Topology

Formal ball

In topology, a formal ball is an extension of the notion of ball to allow unbounded and negative radius. The concept of formal ball was introduced by Weihrauch and Schreiber in 1981 and the negative radius case (the generalized formal ball) by Tsuiki and Hattori in 2008. Specifically, if is a metric space and the nonnegative real numbers, then an element of is a formal ball. Elements of are known as generalized formal balls. Formal balls possess a partial order defined by if , identical to that defined by set inclusion. Generalized formal balls are interesting because this partial order works just as well for as for , even though a generalized formal ball with negative radius does not correspond to a subset of . Formal balls possess the Lawson topology and the . (Wikipedia).

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Formal Definition of a Function using the Cartesian Product

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From playlist Discrete Math (Full Course: Sets, Logic, Proofs, Probability, Graph Theory, etc)

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The formal definition of a sequence.

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From playlist Discrete Math (Full Course: Sets, Logic, Proofs, Probability, Graph Theory, etc)

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Prealgebra Lecture 3.1 Part 1

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Prealgebra Lecture 3.1 Part 9

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Prealgebra Lecture 3.1 Part 3

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Prealgebra Lecture 3.1 Part 8

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From playlist Prealgebra Playlist 1

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Prealgebra Lecture 3.1 Part 2

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From playlist Prealgebra Playlist 1

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Lecture 2A: What is a "Mesh?" (Discrete Differential Geometry)

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From playlist Discrete Differential Geometry - CMU 15-458/858

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Prealgebra Lecture 3.1 Part 4

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From playlist Prealgebra Playlist 1

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Flexibility in symplectic and contact geometry – Emmy Murphy – ICM2018

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From playlist Geometry

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3 - Kick-off afternoon : Thomas Hales, Formalizing the proof of the Kepler Conjecture

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From playlist T2-2014 : Semantics of proofs and certified mathematics

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Zero Knowledge Proofs - Seminar 1 - Introduction

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Quantum computing with noninteracting particles - Alex Arkhipov

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From playlist Mathematics

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Oleg Lazarev - Simplifying Weinstein Morse functions

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From playlist 2018 RTG mini-conference on low-dimensional topology and its interactions with symplectic geometry II

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[BOURBAKI 2017] 11/03/2017 - 3/4 - Patrick MASSOT

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From playlist BOURBAKI - 2017

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Matteo Gori - 2nd-Quantization of Many-Body Dispersion Formalism: Modeling of Million Atom Systems

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From playlist 2022 Multiscale Approaches in Quantum Mechanics Workshop

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Some Recent Insights on Transfer Learning - Samory Kpotufe

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From playlist Mathematics

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Prealgebra Lecture 3.1 Part 5

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Andreas E. Feldmann: A (1+ε)-embedding of low highway dimension graphs into bounded treewidth graphs

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From playlist HIM Lectures 2015

Related pages

Lawson topology | Ball (mathematics) | Topology | Metric space