ProofShift.sv_x: law of lawful-bytes@0.1.1.0
Import: import lawful-bytes@0.1.1.0/proof_shift.bend as ProofShift
Lines 352-366 of lawful-bytes@0.1.1.0/proof_shift.bend: https://jend.leeeet.dev/read.txt?path=lawful-bytes@0.1.1.0/proof_shift.bend&start_line=352&end_line=366

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

# The byte read at p is element j of drop(xs, k).
law sv_x:
  for +len: U32
  for +t: P.Tree<U32>
  for +d: Nat
  for +k: U32
  for +tb: P.Tree<U32>
  for +j: U32
  for +p: U32
  for +h0: {D.ok(C.BT(len, t), d) == True{} : Bool}
  for +hb: {D.ok(C.BT(len, tb), d) == True{} : Bool}
  for +hp: {U32.to_nat(p) == Nat.add(U32.to_nat(j), U32.to_nat(k)) : Nat}
  for +hv: {D.view(C.BT(len, tb)) == SV(D.view(C.BT(len, t)), U32.to_nat(k), U32.to_nat(j)) : List<&2, U32>}
  for +hlt: {Nat.is_lt(Nat.add(U32.to_nat(j), U32.to_nat(k)), U32.to_nat(len)) == True{} : Bool}
  {List.get(&2, U32, List.drop(&2, U32, D.view(C.BT(len, t)), U32.to_nat(k)), U32.to_nat(j)) == Some{C.AT(len, tb, p)} : Maybe<&2, U32>}

Uses (24):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.drop
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.get
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.is_lt
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.to_nat
  https://jend.leeeet.dev/definition.txt?path=lawful-arrays@0.1.0.0/proof_base.bend&name=subst
  https://jend.leeeet.dev/definition.txt?path=lawful-arrays@0.1.0.0/proof_tree.bend&name=Tree
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/defs.bend&name=ok
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/defs.bend&name=view
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=AT
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=BT
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=at_view_t
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=ok_d
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=ok_full
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_core.bend&name=ok_len
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_shift.bend&name=SV
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_shift.bend&name=sv_jd
  https://jend.leeeet.dev/definition.txt?path=lawful-bytes@0.1.1.0/proof_shift.bend&name=sv_read