摘要
Let X be a topological space, I a real interval and Psi a real-valued function on X x I. In this paper, we prove that if C is lower semicontinuous and inf-compact in X, quasi-concave and continuous in I and satisfies sup(I) inf(X) Psi < inf(X) sup(I) Psi, then there exists lambda* is an element of I such that Psi(.,lambda*) has at least two global minima. An application involving the integral functional of the calculus of variations is also presented.
- 出版日期2010