def positive_has_last

stelliferous@0.0.2.0 · proofs/nat_order.bend:64

import Base
import stelliferous@0.0.2.0/proofs/word_encoding.bend as WordEncoding

64def positive_has_last(+size: Nat,positive: {Nat.is_lt(0n,size) == True{} : Bool}) -> {1n+Nat.sub(size,1n) == size : Nat}:
65  match size:
66    case 0n: Empty.absurd({1n == 0n : Nat},WordEncoding.false_true(positive))
67    case 1n+ +rest:
68      %subtract_zero(rest) : {1n+Nat.sub(rest,0n) == 1n+_ : Nat}
69      {==}