Geometry and Topology in Physical Models


International PhD Programme in Mathematics, Mathematical Physics and Computer Science


14. Cegrell classes of plurisubharmonic functions

Polish supervisor: S³awomir Ko³odziej
Cooperating partners: Urban Cegrell (Umea University, Sweden)
Ahmed Zeriahi (Universite Paul Sabatier, Toulouse)


In 1998 Cegrell introduced finite p-energy classes of plurisubharmonic, possibly unbounded functions, and gave a characterization of measures for which complex Monge-Ampère equation has weak solutions within those classes. Further work lead to a description of the maximal domain of definition of the Monge-Ampère operator and a natural question arises about the range of that operator. It is now known that for measures vanishing on pluripolar sets the Dirichlet problem is solvable. However if a measure lives on a pluripolar set then only in some particular cases one can solve the problem. Guedj and Zeriahi carried over the Cegrell's finite energy methods to the study of the Monge-Ampère equation on compact Kähler manifolds. It was successfully applied to some geometrical problems like a proof of the existence of generalized Kähler-Einstein metrics.

In Cegrell's approach some ideas of classical potential theory, energy methods, are implemented in the setting of non-linear pluripotential theory. This non-linearity makes the theory much more difficult as compared to the classical counterpart. Thus, for instance, the maximal plurisubharmonic functions which correspond to harmonic functions in the classical case are not in general continuous, let alone smooth. Therefore pluripotential theory must use a lot of other tools like positive currents.

The aims of this project are the following: find necessary and sufficient conditions on a measure for which the Dirichlet problem for the Monge-Ampère equation is solvable under classical or generalized boundary conditions; describe the boundary values of functions belonging to the maximal domain of definition of the Monge-Ampère operator; solve the Monge-Ampère equation on compact Kähler manifolds for measures possibly supported on pluripolar sets. Here partial results are also interesting provided the progress is significant.