The original version of this story appeared in Quanta Magazine. Calculus is a powerful mathematical tool. But for hundreds of years after its invention in the 17th century, it stood on a shaky ...

The operator convex functions of several variables are characterized in terms of a non-commutative generalization of Jensen's inequality, extending previous results of F. Hansen and G.K. Pedersen for ...

Mathematics majors learn knowledge and awareness of topics such as basic real analysis of one variable, calculus of several variables and vector analysis, and the structure of mathematical proofs.