fact: Definition not_impl4 := λ"t" λ"f" "f" @ (callcc @ "t") @ (callcc @ (λ"g" "t" @ λ"a" "g")) @ (callcc @ (λ"g" "t" @ λ"a" λ"b" "g")) @ (callcc @ (λ"g" "t" @ λ"a" λ"b" λ"c" "g")) @ λ"e" "t" @ λ"a" λ"b" λ"c" λ"d" "e".
imports: ClassicalRealizability.Tactics ClassicalRealizability.BasicResults ClassicalRealizability.Subtyping