Multiplicity results of periodic solutions for a class of first order delay differential equations
The paper is concerned with the periodic boundary value problem of a class of first order differential equations with both delay and advance deviating arguments NEWLINE\[NEWLINEu'(t)=-\Lambda u(t+r)-f(t,u(t-r)), u(0)=-u(2r), u(0)=u(4r),NEWLINE\]NEWLINE where \(r>0\) is a given constant, \(\Lambda\in (-\pi/(2r),3\pi/(2r))\), \(f\) is continuous and such that \(f(t+r,z)=f(t,z)\). Multiplicity results of periodic solutions of the BVP are obtained via some recent critical point theorems for strongly indefinite functionals.
scientific article; zbMATH DE number 6030418
scientific article