law tl_val

lawful-bytes@0.1.1.0 · proof_same.bend:245

import Base
import lawful-bytes@0.1.1.0/defs.bend as D
import lawful-bytes@0.1.1.0/proof_core.bend as C
import lawful-arrays@0.1.0.0/proof_tree.bend as P

245# Byte j, for j = m + s below len, is element m + s of the view.
246law tl_val:
247  for +m: Nat
248  for +len: U32
249  for +t: P.Tree<U32>
250  for +d: Nat
251  for +s: U32
252  for +j: U32
253  for +h: {D.ok(C.BT(len, t), d) == True{} : Bool}
254  for +hj: {U32.to_nat(j) == Nat.add(m, U32.to_nat(s)) : Nat}
255  for +hs: {Nat.is_lt(Nat.add(m, U32.to_nat(s)), U32.to_nat(len)) == True{} : Bool}
256  {List.get(&2, U32, D.view(C.BT(len, t)), Nat.add(m, U32.to_nat(s))) == Some{C.AT(len, t, j)} : Maybe<&2, U32>}