We characterize mildly mixing group actions of a noncompact, locally compact, second countable group G using orbit equivalence. We show an amenable action Φ of G is mildly mixing if and only if G is amenable and for any nonsingular ergodic G-action Ψ, the product G-action Φ×Ψ is orbit equivalent to Ψ. We extend the result to the case of finite measure preserving noninvertible endomorphisms, i.e., when G=N, and show that the theorem cannot be extended to include nonsingular mildly mixing endomorphisms.

The first author was supported in part by the IMA with funds provided by the NSF & NSF grant DMS# 9203489

The second author was partially supported by NSF grant DMS #9214077