| import Mathlib |
| import OAI.Computability.MinUncut.Machines.Runtime |
|
|
| namespace OAI |
|
|
| section |
| namespace MinUncutGames.Foundations.Hastad.SourceMachine |
|
|
| open Turing |
| open MinUncutGames.Foundations.Complexity |
|
|
| variable {K Λ σ : Type} [DecidableEq K] |
|
|
| abbrev Alphabet (_ : K) := Bool |
|
|
| def fieldLoop (source destination : K) (loopLabel : Λ) (exit : Option Λ) : |
| TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool) := |
| .pop source (fun state head => (state.1, head)) |
| (.branch (fun state => state.2.getD false) |
| (.push destination (fun _ => true) (.goto fun _ => loopLabel)) |
| (.load (fun state => (state.1, none)) |
| (Reduction.MachineTransfer.exitAt destination exit))) |
|
|
| def fieldStart (destination : K) (loopLabel : Λ) : |
| TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool) := |
| .push destination (fun _ => false) (.goto fun _ => loopLabel) |
|
|
| def fieldTapes (source destination : K) (base : K → List Bool) |
| (input output : List Bool) : K → List Bool := |
| Function.update (Function.update base source input) destination output |
|
|
| @[simp] theorem fieldTapes_source (source destination : K) (hne : source ≠ destination) |
| (base : K → List Bool) (input output : List Bool) : |
| fieldTapes source destination base input output source = input := by |
| simp [fieldTapes, hne] |
|
|
| @[simp] theorem fieldTapes_destination (source destination : K) |
| (base : K → List Bool) (input output : List Bool) : |
| fieldTapes source destination base input output destination = output := by |
| simp [fieldTapes] |
|
|
| @[simp] theorem fieldTapes_self (source destination : K) (base : K → List Bool) : |
| fieldTapes source destination base (base source) (base destination) = base := by |
| simp [fieldTapes] |
|
|
| theorem fieldTapes_other (source destination p : K) |
| (hpS : p ≠ source) (hpD : p ≠ destination) |
| (base : K → List Bool) (input output : List Bool) : |
| fieldTapes source destination base input output p = base p := by |
| simp [fieldTapes, hpS, hpD] |
|
|
| private theorem update_field_source (source destination : K) (hne : source ≠ destination) |
| (base : K → List Bool) (input output replacement : List Bool) : |
| Function.update (fieldTapes source destination base input output) source replacement = |
| fieldTapes source destination base replacement output := by |
| funext p |
| by_cases hs : p = source |
| · subst p; simp [fieldTapes, hne] |
| · by_cases hd : p = destination |
| · subst p; simp [fieldTapes, Ne.symm hne] |
| · simp [fieldTapes, hs, hd] |
|
|
| private theorem update_field_destination (source destination : K) |
| (base : K → List Bool) (input output replacement : List Bool) : |
| Function.update (fieldTapes source destination base input output) destination replacement = |
| fieldTapes source destination base input replacement := by |
| simp [fieldTapes] |
|
|
| theorem fieldStep_delimiter (source destination : K) (hne : source ≠ destination) |
| (loopLabel : Λ) (exit : Option Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atLoop : program loopLabel = fieldLoop source destination loopLabel exit) |
| (base : K → List Bool) (suffix output : List Bool) (ambient : σ) (register : Option Bool) : |
| TM2.step program |
| ⟨some loopLabel, (ambient, register), fieldTapes source destination base (false :: suffix) output⟩ = |
| some ⟨exit, (ambient, none), fieldTapes source destination base suffix output⟩ := by |
| change some (TM2.stepAux (program loopLabel) (ambient, register) |
| (fieldTapes source destination base (false :: suffix) output)) = _ |
| rw [atLoop] |
| cases exit <;> |
| simp [fieldLoop, Reduction.MachineTransfer.exitAt, TM2.stepAux, hne, update_field_source] |
|
|
| theorem fieldStep_true (source destination : K) (hne : source ≠ destination) |
| (loopLabel : Λ) (exit : Option Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atLoop : program loopLabel = fieldLoop source destination loopLabel exit) |
| (base : K → List Bool) (input output : List Bool) (ambient : σ) (register : Option Bool) : |
| TM2.step program |
| ⟨some loopLabel, (ambient, register), fieldTapes source destination base (true :: input) output⟩ = |
| some ⟨some loopLabel, (ambient, some true), |
| fieldTapes source destination base input (true :: output)⟩ := by |
| change some (TM2.stepAux (program loopLabel) (ambient, register) |
| (fieldTapes source destination base (true :: input) output)) = _ |
| rw [atLoop] |
| simp [fieldLoop, TM2.stepAux, hne, update_field_source, update_field_destination] |
|
|
| theorem fieldLoopTrace (source destination : K) (hne : source ≠ destination) |
| (loopLabel : Λ) (exit : Option Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atLoop : program loopLabel = fieldLoop source destination loopLabel exit) |
| (base : K → List Bool) (n : Nat) (suffix output : List Bool) |
| (ambient : σ) (register : Option Bool) : |
| (MachineComposition.advance (TM2.step program))^[n + 1] |
| (some ⟨some loopLabel, (ambient, register), |
| fieldTapes source destination base (encodeWord n ++ suffix) output⟩) = |
| some ⟨exit, (ambient, none), |
| fieldTapes source destination base suffix (List.replicate n true ++ output)⟩ := by |
| induction n generalizing output register with |
| | zero => |
| simpa only [Nat.zero_add, Function.iterate_one, MachineComposition.advance_some, |
| encodeWord, List.replicate_zero, List.nil_append, List.singleton_append] using |
| fieldStep_delimiter source destination hne loopLabel exit program atLoop |
| base suffix output ambient register |
| | succ n ih => |
| rw [Function.iterate_succ_apply] |
| simp only [encodeWord, List.replicate_succ, List.cons_append] |
| change (MachineComposition.advance (TM2.step program))^[n + 1] |
| (TM2.step program ⟨some loopLabel, (ambient, register), |
| fieldTapes source destination base (true :: (encodeWord n ++ suffix)) output⟩) = _ |
| rw [fieldStep_true source destination hne loopLabel exit program atLoop, ih] |
| have hrotate : List.replicate n true ++ true :: output = |
| true :: (List.replicate n true ++ output) := by |
| calc |
| _ = (List.replicate n true ++ [true]) ++ output := by simp |
| _ = List.replicate (n + 1) true ++ output := by rw [List.replicate_succ'] |
| _ = _ := by rw [List.replicate_succ, List.cons_append] |
| rw [hrotate] |
| |
| theorem fieldStartStep (source destination : K) |
| (startLabel loopLabel : Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atStart : program startLabel = fieldStart destination loopLabel) |
| (base : K → List Bool) (input output : List Bool) (ambient : σ) (register : Option Bool) : |
| TM2.step program |
| ⟨some startLabel, (ambient, register), fieldTapes source destination base input output⟩ = |
| some ⟨some loopLabel, (ambient, register), |
| fieldTapes source destination base input (false :: output)⟩ := by |
| change some (TM2.stepAux (program startLabel) (ambient, register) |
| (fieldTapes source destination base input output)) = _ |
| rw [atStart] |
| simp [fieldStart, TM2.stepAux, update_field_destination] |
| |
| def fieldInTime (source destination : K) (hne : source ≠ destination) |
| (startLabel loopLabel : Λ) (exit : Option Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atStart : program startLabel = fieldStart destination loopLabel) |
| (atLoop : program loopLabel = fieldLoop source destination loopLabel exit) |
| (base : K → List Bool) (n : Nat) (suffix : List Bool) |
| (hinput : base source = encodeWord n ++ suffix) |
| (ambient : σ) (register : Option Bool) : |
| StateTransition.EvalsToInTime (TM2.step program) |
| ⟨some startLabel, (ambient, register), base⟩ |
| (some ⟨exit, (ambient, none), |
| fieldTapes source destination base suffix (encodeWord n ++ base destination)⟩) |
| (n + 2) where |
| steps := n + 2 |
| evals_in_steps := by |
| have hbase : fieldTapes source destination base (encodeWord n ++ suffix) |
| (base destination) = base := by rw [← hinput, fieldTapes_self] |
| conv_lhs => rw [← hbase] |
| change (MachineComposition.advance (TM2.step program))^[(n + 1) + 1] |
| (some ⟨some startLabel, (ambient, register), |
| fieldTapes source destination base (encodeWord n ++ suffix) (base destination)⟩) = _ |
| rw [Function.iterate_succ_apply] |
| change (MachineComposition.advance (TM2.step program))^[n + 1] |
| (TM2.step program ⟨some startLabel, (ambient, register), |
| fieldTapes source destination base (encodeWord n ++ suffix) (base destination)⟩) = _ |
| rw [fieldStartStep source destination startLabel loopLabel program atStart, |
| fieldLoopTrace source destination hne loopLabel exit program atLoop] |
| simp [encodeWord, List.append_assoc] |
| steps_le_m := Nat.le_refl _ |
| |
| def afterField (source destination : K) (base : K → List Bool) |
| (n : Nat) (suffix : List Bool) : K → List Bool := |
| fieldTapes source destination base suffix (encodeWord n ++ base destination) |
| |
| def fieldNext (start : Fin 4 → Λ) (exit : Option Λ) (j : Fin 4) : Option Λ := |
| match j.val with |
| | 0 => some (start 1) |
| | 1 => some (start 2) |
| | 2 => some (start 3) |
| | _ => exit |
| |
| def fourTapes (source : K) (destination : Fin 4 → K) (base : K → List Bool) |
| (a b c d : Nat) (suffix : List Bool) : K → List Bool := |
| let t₀ := afterField source (destination 0) base a (encodeWords [b, c, d] ++ suffix) |
| let t₁ := afterField source (destination 1) t₀ b (encodeWords [c, d] ++ suffix) |
| let t₂ := afterField source (destination 2) t₁ c (encodeWords [d] ++ suffix) |
| afterField source (destination 3) t₂ d suffix |
| |
| theorem fourTapes_source (source : K) (destination : Fin 4 → K) |
| (hsep : ∀ j, source ≠ destination j) (base : K → List Bool) |
| (a b c d : Nat) (suffix : List Bool) : |
| fourTapes source destination base a b c d suffix source = suffix := by |
| simp [fourTapes, afterField, hsep] |
| |
| theorem fourTapes_other (source : K) (destination : Fin 4 → K) |
| (p : K) (hpS : p ≠ source) (hpD : ∀ j, p ≠ destination j) |
| (base : K → List Bool) (a b c d : Nat) (suffix : List Bool) : |
| fourTapes source destination base a b c d suffix p = base p := by |
| simp [fourTapes, afterField, fieldTapes_other, hpS, hpD] |
| |
| theorem fourField_time_eq_length (a b c d : Nat) : |
| a + b + c + d + 8 = (encodeWords [a, b, c, d]).length + 4 := by |
| simp [encodeWords, encodeWord] |
| omega |
| |
| def fourFieldsInTime (source : K) (destination : Fin 4 → K) |
| (hsep : ∀ j, source ≠ destination j) |
| (start loopLabel : Fin 4 → Λ) (exit : Option Λ) |
| (program : Λ → TM2.Stmt (Alphabet (K := K)) Λ (σ × Option Bool)) |
| (atStart : ∀ j, program (start j) = fieldStart (destination j) (loopLabel j)) |
| (atLoop : ∀ j, program (loopLabel j) = |
| fieldLoop source (destination j) (loopLabel j) (fieldNext start exit j)) |
| (base : K → List Bool) (a b c d : Nat) (suffix : List Bool) |
| (hinput : base source = encodeWords [a, b, c, d] ++ suffix) |
| (ambient : σ) (register : Option Bool) : |
| StateTransition.EvalsToInTime (TM2.step program) |
| ⟨some (start 0), (ambient, register), base⟩ |
| (some ⟨exit, (ambient, none), fourTapes source destination base a b c d suffix⟩) |
| (a + b + c + d + 8) := by |
| let t₀ := afterField source (destination 0) base a (encodeWords [b, c, d] ++ suffix) |
| let t₁ := afterField source (destination 1) t₀ b (encodeWords [c, d] ++ suffix) |
| let t₂ := afterField source (destination 2) t₁ c (encodeWords [d] ++ suffix) |
| have h₀ : base source = encodeWord a ++ (encodeWords [b, c, d] ++ suffix) := by |
| simpa only [encodeWords, List.append_assoc] using hinput |
| have h₁ : t₀ source = encodeWord b ++ (encodeWords [c, d] ++ suffix) := by |
| simp [t₀, afterField, hsep, encodeWords, List.append_assoc] |
| have h₂ : t₁ source = encodeWord c ++ (encodeWords [d] ++ suffix) := by |
| simp [t₁, afterField, hsep, encodeWords, List.append_assoc] |
| have h₃ : t₂ source = encodeWord d ++ suffix := by |
| simp [t₂, afterField, hsep, encodeWords] |
| have p₀ := fieldInTime source (destination 0) (hsep 0) (start 0) (loopLabel 0) |
| (some (start 1)) program (atStart 0) (atLoop 0) base a |
| (encodeWords [b, c, d] ++ suffix) h₀ ambient register |
| have p₁ := fieldInTime source (destination 1) (hsep 1) (start 1) (loopLabel 1) |
| (some (start 2)) program (atStart 1) (atLoop 1) t₀ b |
| (encodeWords [c, d] ++ suffix) h₁ ambient none |
| have p₂ := fieldInTime source (destination 2) (hsep 2) (start 2) (loopLabel 2) |
| (some (start 3)) program (atStart 2) (atLoop 2) t₁ c |
| (encodeWords [d] ++ suffix) h₂ ambient none |
| have p₃ := fieldInTime source (destination 3) (hsep 3) (start 3) (loopLabel 3) |
| exit program (atStart 3) (atLoop 3) t₂ d suffix h₃ ambient none |
| let p₀₁ := StateTransition.EvalsToInTime.trans _ _ _ _ _ _ p₀ p₁ |
| let p₀₁₂ := StateTransition.EvalsToInTime.trans _ _ _ _ _ _ p₀₁ p₂ |
| let p := StateTransition.EvalsToInTime.trans _ _ _ _ _ _ p₀₁₂ p₃ |
| exact { |
| toEvalsTo := p.toEvalsTo |
| steps_le_m := by have h := p.steps_le_m; omega |
| } |
| |
| def fieldDestination (j : Fin 4) : Fin 5 := ⟨j.val + 1, by omega⟩ |
| |
| theorem fourTapes_concrete (base : Fin 5 → List Bool) (a b c d : Nat) (suffix : List Bool) : |
| fourTapes 0 fieldDestination base a b c d suffix = |
| fun p : Fin 5 => if p = 0 then suffix |
| else if p = 1 then encodeWord a ++ base 1 |
| else if p = 2 then encodeWord b ++ base 2 |
| else if p = 3 then encodeWord c ++ base 3 |
| else encodeWord d ++ base 4 := by |
| funext p |
| have hp : p = 0 ∨ p = 1 ∨ p = 2 ∨ p = 3 ∨ p = 4 := by omega |
| rcases hp with rfl | rfl | rfl | rfl | rfl <;> |
| simp [fourTapes, afterField, fieldTapes, fieldDestination] |
| |
| def groupingProgram (label : Fin 4 × Bool) : |
| TM2.Stmt (fun _ : Fin 5 => Bool) (Fin 4 × Bool) (Unit × Option Bool) := |
| if label.2 then |
| fieldLoop 0 (fieldDestination label.1) (label.1, true) |
| (fieldNext (fun j => (j, false)) none label.1) |
| else fieldStart (fieldDestination label.1) (label.1, true) |
| |
| def groupingMachine : FinTM2 where |
| K := Fin 5 |
| k₀ := 0 |
| k₁ := 1 |
| Γ _ := Bool |
| Λ := Fin 4 × Bool |
| main := (0, false) |
| σ := Unit × Option Bool |
| initialState := ((), none) |
| m := groupingProgram |
| |
| def groupingMachineInTime (base : Fin 5 → List Bool) (a b c d : Nat) (suffix : List Bool) |
| (hinput : base 0 = encodeWords [a, b, c, d] ++ suffix) (register : Option Bool) : |
| StateTransition.EvalsToInTime groupingMachine.step |
| ⟨some (0, false), ((), register), base⟩ |
| (some ⟨none, ((), none), fourTapes (0 : Fin 5) fieldDestination base a b c d suffix⟩) |
| (a + b + c + d + 8) := |
| fourFieldsInTime (0 : Fin 5) fieldDestination (by |
| intro j h |
| have hh := congrArg Fin.val h |
| change 0 = j.val + 1 at hh |
| omega) |
| (fun j => (j, false)) (fun j => (j, true)) none groupingProgram |
| (by intro j; simp [groupingProgram]) (by intro j; simp [groupingProgram]) |
| base a b c d suffix hinput () register |
| |
| end MinUncutGames.Foundations.Hastad.SourceMachine |
| |
| end |
| |
| end OAI |
| |
