35 Partial differential equations -- 35B Qualitative properties of solutions 35B65 Smoothness and regularity of solutions
35 Partial differential equations -- 35K Parabolic equations and systems 35K67 Singular parabolic equations
47 Operator theory -- 47D Groups and semigroups of linear operators, their generalizations and applications 47D07 Markov semigroups and applications to diffusion processes
60 Probability theory and stochastic processes -- 60J Markov processes 60J35 Transition functions, generators and resolvents