Topological Manifolds

• Autorzy: Karol Pąk
• Języki publikacji: EN

Abstrakty

EN

Let us recall that a topological space M is a topological manifold if M is second-countable Hausdorff and locally Euclidean, i.e. each point has a neighborhood that is homeomorphic to an open ball of E n for some n. However, if we would like to consider a topological manifold with a boundary, we have to extend this definition. Therefore, we introduce here the concept of a locally Euclidean space that covers both cases (with and without a boundary), i.e. where each point has a neighborhood that is homeomorphic to a closed ball of En for some n. Our purpose is to prove, using the Mizar formalism, a number of properties of such locally Euclidean spaces and use them to demonstrate basic properties of a manifold. Let T be a locally Euclidean space. We prove that every interior point of T has a neighborhood homeomorphic to an open ball and that every boundary point of T has a neighborhood homeomorphic to a closed ball, where additionally this point is transformed into a point of the boundary of this ball. When T is n-dimensional, i.e. each point of T has a neighborhood that is homeomorphic to a closed ball of En, we show that the interior of T is a locally Euclidean space without boundary of dimension n and the boundary of T is a locally Euclidean space without boundary of dimension n − 1. Additionally, we show that every connected component of a compact locally Euclidean space is a locally Euclidean space of some dimension. We prove also that the Cartesian product of locally Euclidean spaces also forms a locally Euclidean space. We determine the interior and boundary of this product and show that its dimension is the sum of the dimensions of its factors. At the end, we present several consequences of these results for topological manifolds. This article is based on [14].

Słowa kluczowe

EN

locally Euclidean spaces; interior; boundary; Cartesian product

Kategorie tematyczne

• 57N15: Topology of E n , n -manifolds ( 4 n ∞ )
• 03B35: Mechanization of proofs and logical operations

• Wydawca: De Gruyter Open
• Czasopismo: Formalized Mathematics
• Rocznik: 2014
• Tom: 22
• Numer: 2
• Strony: 179-186

Daty

otrzymano

2014-06-16

online

2015-02-05

Twórcy

autor

Karol Pąk

• Institute of Informatics University of Białystok Sosnowa 64, 15-887 Białystok Poland

Bibliografia

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Identyfikatory

DOI

10.2478/forma-2014-0019