China
In the present paper, we investigate the maximum number of limit cycles bifurcating from the period annulus of a cubic isochronous center when it is perturbed by piecewise polynomials of arbitrary degree n with the switching line x = 0. By analyzing the number of zeros of the first order Melnikov function with a new Chebyshev criterion in [3], we show that the sharp upper bound on the number of limit cycles for the perturbed systems is 2n + 1 for n ≥ 1.
© 2008-2026 Fundación Dialnet · Todos los derechos reservados