MULTIPLE PERIODIC-SOLUTIONS OF A SUPERLINEAR FORCED WAVE-EQUATION

We study the existence of forced vibrations of nonlinear wave equation: [GRAPHICS} where g(xi) is-an-element-of C(R, R) is a function with superlinear growth and f(x, t) is a function which is 2pi-periodic in t. Under the suitable growth condition on g(xi), we prove the existence of infinitely many solution of (*) for any given f(x, t).