Convexity of partial differential operators

Commutative Partial Differential Operators

In one variable, there exists a satisfactory classification of commutative rings of differential operators. In several variables, even the simplest generalizations seem to be unknown and in this report we give examples and pose questions that may suggest a theory to be developed. In particular, we address the existence of a “spectral variety” generalizing the spectral curve of the one dimension...

Partial Differential Equations for Morphological Operators

Two of G. Matheron’s seminal contributions have been his development of size distributions (else called ‘granulometries’) and his kernel representation theory. The first deals with semigroups of multiscale openings and closings of binary images (shapes) by compact convex sets, a basic ingredient of which are the multiscale Minkowski dilations and erosions. The second deals with representing inc...

Entropy and convexity for nonlinear partial differential equations.

Partial differential equations are ubiquitous in almost all applications of mathematics, where they provide a natural mathematical description of many phenomena involving change in physical, chemical, biological and social processes. The concept of entropy originated in thermodynamics and statistical physics during the nineteenth century to describe the heat exchanges that occur in the thermal ...

A Microscopic Convexity Principle for Nonlinear Partial Differential Equations

Caffarelli-Friedman [7] proved a constant rank theorem for convex solutions of semilinear elliptic equations in R2, a similar result was also discovered by Yau [28] at the same time. The result in [7] was generalized to R by Korevaar-Lewis [27] shortly after. This type of constant rank theorem is called microscopic convexity principle. It is a powerful tool in the study of geometric properties ...

Linear Operators in the Theory of Partial Differential Equations