def seek_left
import bendtorch-core@0.1.0.0/src/storage/api.bend as Apiimport Base
import bendtorch-core@0.1.0.0/src/storage/arith.bend as Arith
617def seek_left(+p: Nat, +k: Nat, +left: {Nat.add(1n+p, k) == 20n : Nat}) -> {Nat.add(p, 1n+k) == 20n : Nat}:
618 %Equal.sym(Nat, Nat.add(p, 1n+k), 1n+Nat.add(p, k), Arith.add_succ(p, k)) : {_ == 20n : Nat}
619 left