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Articles 1 - 6 of 6
Full-Text Articles in Geometry and Topology
Categories, Homology And Sheaves For Hypergraphs, Robert Green
Categories, Homology And Sheaves For Hypergraphs, Robert Green
Electronic Theses & Dissertations (2024 - present)
Hypergraphs are a prominent tool for representing networks with connections among three or more entities. There is an inherent flexibility that allows hypergraphs to more naturally represent certain types of networks than graphs or simplicial complexes can on their own. This flexibility, however, comes at a cost, as there is a zoo of various categories and homology theories that are applicable to hypergraphs. The first chapter of this dissertation explores various categorical perspectives on hypergraphs, focusing on what the natural notion of morphism between hypergraphs should be. It also contains an exploration of the functoriality of vertex-edge duality in these …
Smooth And Proper Maps With Respect To A Fibration, Mathieu Anel, Jonathan Weinberger
Smooth And Proper Maps With Respect To A Fibration, Mathieu Anel, Jonathan Weinberger
Engineering Faculty Articles and Research
This paper explain how the geometric notions of local contractibility and properness are related to the Σ-types and Π-types constructors of dependent type theory. We shall see how every Grothendieck fibration comes canonically with such a pair of notions—called smooth and proper maps—and how this recovers the previous examples and many more. This paper uses category theory to reveal a common structure between geometry and logic, with the hope that the parallel will be beneficial to both fields. The style is mostly expository, and the main results are proved in external references.
Higher Diffeology Theory, Emilio Minichiello
Higher Diffeology Theory, Emilio Minichiello
Dissertations, Theses, and Capstone Projects
Finite dimensional smooth manifolds have been studied for hundreds of years, and a massive theory has been built around them. However, modern mathematicians and physicists are commonly dealing with objects outside the purview of classical differential geometry, such as orbifolds and loop spaces. Diffeology is a new framework for dealing with such generalized smooth spaces. This theory (whose development started in earnest in the 1980s) has started to catch on amongst the wider mathematical community, thanks to its simplicity and power, but it is not the only approach to dealing with generalized smooth spaces. Higher topos theory is another such …
An Explicit Construction Of Sheaves In Context, Tyler A. Bryson
An Explicit Construction Of Sheaves In Context, Tyler A. Bryson
Dissertations, Theses, and Capstone Projects
This document details the body of theory necessary to explicitly construct sheaves of sets on a site together with the development of supporting material necessary to connect sheaf theory with the wider mathematical contexts in which it is applied. Of particular interest is a novel presentation of the plus construction suitable for direct application to a site without first passing to the generated grothendieck topology.
Bicategorical Traces And Cotraces, Justin Barhite
Bicategorical Traces And Cotraces, Justin Barhite
Theses and Dissertations--Mathematics
Familiar constructions like the trace of a matrix and the Euler characteristic of a closed smooth manifold are generalized by a notion of trace of an endomorphism of a dualizable object in a bicategory equipped with a piece of additional structure called a shadow functor. Another example of this bicategorical trace, in the form of maps between Hochschild homology of bimodules, appears in a 1987 paper by Joseph Lipman, alongside a more mysterious ”cotrace” map involving Hochschild cohomology. Putting this cotrace on the same category-theoretic footing as the trace has led us to propose a ”bicategorical cotrace” in a closed …
Unique Lifting To A Functor, Mark Myers
Unique Lifting To A Functor, Mark Myers
West Chester University Master’s Theses
We develop a functorial approach to quotient constructions, defining morphisms quotient relative to a functor and the dual concept of unique liftings relative to a functor. Various classes of epimorphism are given detailed analysis and their relationship to quotient morphisms characterized. The behavior of unique lifting morphisms with respect to products, equalizers, and general limits in a category are studied. Applications to generalized covering space theory, coreflective subcategories of topological spaces, topological groups and rings, and Galois theory are explored. Finally, we give conditions for the product of two quotient morphisms to be quotient in a braided monoidal closed category.