Resonant codimension-two bifurcation for van der Pol equation with different discrete-time delays

The van der Pol equation with different discrete-time delay is analyzed. The resonant codimension-two bifurcation can be found, at which the transcendental characteristic equation possesses two pairs of pure imaginary roots, plusmniomega₁, plusmn iomega₂ with omega₁ : omega₂ = m:n, where m and n are positive integers. Some numerical simulation examples for justifying the theoretical analysis are also given.