Definition
A real valued function f : X → R defined on a convex set X in a vector space is called convex if, for any two points and in X and any ,
The function is called strictly convex if
for every, and .
A function f is said to be (strictly) concave if −f is (strictly) convex.
Read more about this topic: Convex Function
Famous quotes containing the word definition:
“... we all know the wag’s definition of a philanthropist: a man whose charity increases directly as the square of the distance.”
—George Eliot [Mary Ann (or Marian)
“The man who knows governments most completely is he who troubles himself least about a definition which shall give their essence. Enjoying an intimate acquaintance with all their particularities in turn, he would naturally regard an abstract conception in which these were unified as a thing more misleading than enlightening.”
—William James (1842–1910)
“I’m beginning to think that the proper definition of “Man” is “an animal that writes letters.””
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