Istari

Miscellaneous

This module contains various constants that need to be primitive, but aren’t used widely enough to make them pervasive.

Constant Usage
bogus used for placeholder terms
entailment a pseudo-relation used in the rewriter
magic the extract for trustme
orphan substituted for variables going out of scope
positive arises in determining whether mu types are well-formed
negative arises in determining whether mu types are well-formed

It also contains some defined notions that defy categorization:

nonsense : U 0
         = void -g> void

The important property of nonsense is everything belongs to nonsense, even terms that would normally be ill-formed. As a corollary, every type is a subtype of nonsense:

nonsense_subtype : forall (i : level) (a : U i) . a <: nonsense