Decoded sparse-address equality — proof internals #
theorem
Complexity.RAM.RegisterStore.Machine.decodedAddressEqTM_reachesIn_frame_internal
{n : ℕ}
(addressIdx queryIdx resultIdx : Fin n)
(hdistinct : TM.BinaryEqDistinct addressIdx queryIdx resultIdx)
(addressBits queryBits : List Bool)
(inp₀ : Tape)
(work₀ : Fin n → Tape)
(out₀ : Tape)
(haddress : (work₀ addressIdx).HasBinaryPrefix addressBits)
(haddressStart : (work₀ addressIdx).cells 0 = Γ.start)
(hquery : (work₀ queryIdx).HasBinaryString queryBits)
(hqueryStart : (work₀ queryIdx).cells 0 = Γ.start)
(hresult : (work₀ resultIdx).HasBinaryPrefix [])
(hinput : inp₀.read ≠ Γ.start)
(hother : ∀ (i : Fin n), i ≠ addressIdx → i ≠ queryIdx → i ≠ resultIdx → (work₀ i).read ≠ Γ.start ∧ 1 ≤ (work₀ i).head)
(houtput : out₀.read ≠ Γ.start)
(houtputHead : 1 ≤ out₀.head)
:
∃ (c' : Complexity.Cfg n (decodedAddressEqTM addressIdx queryIdx resultIdx).Q),
∃ t ≤ decodedAddressEqTime addressBits queryBits,
(decodedAddressEqTM addressIdx queryIdx resultIdx).reachesIn t
{ state := (decodedAddressEqTM addressIdx queryIdx resultIdx).qstart, input := inp₀, work := work₀,
output := out₀ }
c' ∧ (decodedAddressEqTM addressIdx queryIdx resultIdx).halted c' ∧ c'.input = inp₀ ∧ (c'.work resultIdx).HasBinaryPrefix [decide (addressBits = queryBits)] ∧ (c'.work addressIdx).HasBinaryContent addressBits ∧ 1 ≤ (c'.work addressIdx).head ∧ (c'.work addressIdx).cells 0 = Γ.start ∧ (c'.work queryIdx).HasBinaryContent queryBits ∧ 1 ≤ (c'.work queryIdx).head ∧ (c'.work queryIdx).cells 0 = Γ.start ∧ (∀ (i : Fin n), i ≠ addressIdx → i ≠ queryIdx → i ≠ resultIdx → c'.work i = work₀ i) ∧ c'.output = out₀