def internal_mem_append_right
bend-mathlib@0.8.1.0 · list.bend:747
import bend-mathlib@0.8.1.0/list.bend as List
import Base
747def internal_mem_append_right(+xs: List<&2, Nat>, +ys: List<&2, Nat>, +x: Nat, h: {List.contains(~Nat, ~Nat.is_eq, ys, x) == True{} : Bool}) -> {List.contains(~Nat, ~Nat.is_eq, List.append(&2, Nat, xs, ys), x) == True{} : Bool}:
748 match xs:
749 case Nil{}:
750 h
751 case hd <> tl:
752 %internal_contains_cons(~Nat, ~Nat.is_eq, hd, List.append(&2, Nat, tl, ys), x) : {_ == True{} : Bool}
753 internal_or_of_right(Nat.is_eq(hd, x), List.contains(~Nat, ~Nat.is_eq, List.append(&2, Nat, tl, ys), x), internal_mem_append_right(tl, ys, x, h))