Existence and Spatio-Temporal Patterns of Periodic Solutions to Second Order Non-Autonomous Equivariant Delayed Systems

Existence and spatio-temporal symmetric patterns of periodic solutions to second order reversible equivariant non-autonomous periodic systems with multiple delays are studied under the Hartman-Nagumo growth conditions. The method is based on using the Brouwer $D_1 times mathbb Z_2times Gamma$-equivariant degree theory, where $D_1$ is related to the reversing symmetry, $mathbb Z_2$ is related to the oddness of the right-hand-side and $Gamma$ reflects the symmetric character of the coupling in the corresponding network. Abstract results are supported by a concrete example with $Gamma = D_n$ -- the dihedral group of order $2n$.