def le_sc
import bend-collections-laws-math@1.0.0.0/proofs/lib/arith.bend as Arithimport Base
import bend-collections-laws-math@1.0.0.0/proofs/lib/nat.bend as N
57def le_sc(+k: Nat, +x: Nat) -> {Nat.is_le(x, sc(k, x)) == True{} : Bool}:
58 match k:
59 case 0n:
60 N.le_refl(x)
61 case 1n+j:
62 N.le_trans(x, sc(j, x), Nat.double(sc(j, x)), le_sc(j, x), N.double_self_le(sc(j, x)))