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Borsuk-Ulam Property for Graphs II: The Zn-Action

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Autor(es):
Goncalves, D. L. ; Gonzalez, J.
Número total de Autores: 2
Tipo de documento: Artigo Científico
Fonte: LOBACHEVSKII JOURNAL OF MATHEMATICS; v. 46, n. 3, p. 19-pg., 2025-03-01.
Resumo

For a finite group H and connected topological spaces X and Y such that X is endowed with a free left H-action tau, we provide a geometric condition in terms of the existence of a commutative diagram of spaces (arising from the triple (X, Y; tau)) to decide whether the Borsuk-Ulam property holds for based homotopy classes alpha is an element of[X, Y]0, as well as for free homotopy classes alpha is an element of[X, Y]. Here a homotopy class alpha is said to satisfy the Borsuk-Ulam property if, for each of its representatives f is an element of alpha, there exists an H-orbit, where f fails to be injective. Our geometric characterization is attained by constructing an H-equivariant map fromX to the classical configuration space F|H|(Y). We derive an algebraic condition from the geometric characterisation, and show that former one is in fact equivalent to the latter one whenX and Y are aspherical. We then specialize to the 1-dimensional case, i.e., whenX is an arbitrary connected graph, H is cyclic, and Y is either a tree, a circle, or the connected graph S1 boolean OR I with two vertices and two edges one of which is a loop and the other is a closed interval. The graph-braid-group ingredient in our characterizations is then effectively controlled through the use of discreteMorse theory. (AU)

Processo FAPESP: 22/16455-6 - Topologia algébrica, geométrica e diferencial
Beneficiário:Daciberg Lima Gonçalves
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 16/24707-4 - Topologia algébrica, geométrica e diferencial
Beneficiário:Daciberg Lima Gonçalves
Modalidade de apoio: Auxílio à Pesquisa - Temático