Multiple mixing from weak hyperbolicity by the Hopf argument

We show that using only weak hyperbolicity (no smoothness, compactness or exponential rates) the Hopf argument produces multiple mixing in an elementary way. While this recovers classical results with far simpler proofs, the point is the broader applicability implied by the weak hypotheses. Some of the results can also be viewed as establishing "mixing implies multiple mixing" outside the classical hyperbolic context.