Número de Nielsen-Borsuk-Ulam para aplicações entre toros

Abstract

The Nielsen-Borsuk-Ulam number is a lower bound for the minimal number of pair of coincidences points such that f(x) = f(\tau(x)) in a given homotopy class of maps. In this text the Nielsen-Borsuk-Ulam number, NBU(f; \tau), is calculated for any mapsf : T^n \to T^n where T^n is the torus of dimension n with n less than or equal to 3 and \tau is any free involution in Tn. Furthermore, it is concluded that the tori T^1, T^2 and T^3 are Wecken spaces in the Nielsen-Borsuk-Ulam theory and that the triple (Tn; \tau ;Tn) don't have the Borsuk-Ulam property for any free involution \tau.