Monsky–Washnitzer cohomology

In algebraic geometry, Monsky–Washnitzer cohomology is a p-adic cohomology theory defined for non-singular affine varieties over fields of positive characteristic p introduced by Monsky and Washnitzer (1968) and Monsky (1968), who were motivated by the work of Dwork (1960). The idea is to lift the variety to characteristic 0, and then take a suitable subalgebra of the algebraic de Rham cohomology of Grothendieck (1966). The construction was simplified by van der Put (1986). Its extension to more general varieties is called rigid cohomology.