On a vanishing theorem for birational morphisms of threefolds in positive and mixed characteristics

Abstract: We prove a relative Kawamata Viehweg vanishing type theorem for birational morphisms. We use this to prove a Grauert Riemenschneider theorem over log canonical threefolds without zero dimensional log canonical centers, in residue characteristic p greater than five. In large enough residue characteristics, we prove a Grauert Riemenschneider theorem over threefold log canonical singularities with standard coefficients. These vanishing theorems can also be used to study the depth of log canonical singularities at non log canonical centers, as well as the singularities of the log canonical centers themselves. The former simplifies joint work with F. Bernasconi and Z. Patakfalvi, and the latter appears in joint work with Q. Posva.