Works
- Sur les fonctions convexes et les inégalités entre les valeurs moyennes, Acta Mathematica, 1906
In Thinking Tools
Known for
A Danish telephone engineer who did mathematics in his spare time, he proved what is now Jensen's inequality: for a convex function, the function of an average is at most the average of the function. It is the formal basis for saying that variability helps a convex payoff and hurts a concave one.