In previous work we describe a novel approach to dependent typing based on a
multivalued term language. In this technical report we formalise the runtime, a
kind of operational semantics, for that language. We describe a fairly
comprehensive core language, and then give a small-step operational semantics
based on an abstract machine. Errors are explicit in the semantics. We also
prove several simple properties: that every non-terminated machine state steps
to something and that reduction is deterministic once input is fixed

Glew, Neal