Multiple periodic solutions to a class of second-order nonlinear mixed-type functional differential equations
Xiao-Bao Shu1and Yuan-Tong Xu2
Received22 Oct 2004
Revised23 Aug 2005
Abstract
By means of variational structure and Z2 group index theory, we obtain multiple periodic solutions to a class of second-order mixed-type differential equations x''(t−τ)+f(t,x(t),x(t−τ),x(t−2τ))=0 and x''(t−τ)+λ(t)f1(t,x(t),x(t−τ),x(t−2τ))=x(t−τ).