Interaction Equivalence
summary
Defines a checker lambda calculus with black/white lambdas and applications, four beta rules, and a deterministic head interaction steps count that ignores internal silent reductions. Proves that the resulting interaction equivalence is an equational theory and precisely matches Böhm tree equivalence. Gives a separating example (identity vs EA expansion) that differs by one versus two interaction steps, develops interaction-aware Böhm-out and intersection type proofs, and shows the approach succeeds without adding nondeterminism.
AI-written summary · about