(1) Instituto de Matemática e Estatística, Universidade de São Paulo, CP 20570, 01498 São Paulo, São Paulo, Brasil;(2) Instituto de Física, Universidade de São Paulo, CP 20516, 01498 São Paulo, São Paulo, Brasil
Abstract:
We investigated the structure of the so-called first Hopf bifurcation surface associated to a differential equation with two time delays. A geometrical approach leading naturally to a number theoretic approach provides rigourous results which are corroborated by previous numerical and experimental (optical compound resonator) results.