Convexity Study of Interval Functions and Functionals & Fuzzy Functions and Functionals

The writer in this paper, on their foundation, discusses the convexity of interval and fuzzy function, interval and fuzzy functional variation. Besides he gives the definition of a convex function and convex functional about an interval, a common function at fuzzy points, a fuzzy-valued function at common points and a fuzzy-valued function at fuzzy points, and judges their convexity condition. This lays a foundation on the application of fuzzy optimal theories and fuzzy variation methods at physical and approximate calculation. And finally he illustrates their application by example.