This paper examines properties and interrelations of several concepts of generalized concavity. It shows that the class of functions that are both 'generalized concave' and 'generalized convex' is ...

The saddle function results provide a foundation for the sensitivity analysis of primal and dual optimal solutions to general finite-dimensional problems in convex optimization, since such solutions ...

We compare and contrast concave and convex lenses by drawing ray diagrams.

Our brains trick us into seeing images of craters as both concave and convex.