Adequacy for Algebraic Effects Revisited

This paper proves an adequacy theorem for a general class of algebraic effects, including infinitary ones. The theorem targets a version of Call-by-Push-Value (CBPV), so that it applies to many possible evaluation mechanisms, including call-by-value. The calculus is given an operational semantics based on interaction trees, as well as a denotational semantics based on monad algebras. The main result, viz. that denotational equivalence implies observational equivalence, using a traditional logical relations argument.