Shi, Shuzhong Equivalence between Ekeland’s variational principle and Caristi’s fixed point theorem. (Chinese. English summary) Zbl 0621.54030 Adv. Math., Beijing 16, No. 2, 203-206 (1987). This paper gives a direct proof of the equivalence between Ekeland’s variational principle and Caristi’s fixed point theorem, and proposes a formally stronger Caristi’s fixed point theorem. By this theorem, we can improve Clarke’s fixed point theorem for directional contractions. Cited in 4 ReviewsCited in 8 Documents MSC: 54H25 Fixed-point and coincidence theorems (topological aspects) PDFBibTeX XMLCite \textit{S. Shi}, Adv. Math., Beijing 16, No. 2, 203--206 (1987; Zbl 0621.54030)