openAI-math-dataset / lean /OAI /Computability /Logspace /RecursivePrograms.lean
roseking's picture
Sync from openai/math@faee2cf485a8 (part 12)
1905fc7 verified
Raw History Blame Contribute Delete
54.5 kB
import OAI.Computability.Logspace.CounterPrograms
namespace OAI
/-!
Measured stack encodings and the realization of recursive programs with simultaneous space bounds.
From OpenAI, *Exact Derandomization of Logarithmic Space: L = RL = BPL*.
-/
set_option autoImplicit true
section
/-! Measured encodings. `cord` appends with overhead on just the new
piece, not the previously suspended stack. -/
namespace ExactDerandomization.Relay
open Counter
def lb (x : ℕ) := x.log2+1
lemma lb_pos (x) : 0<lb x := by dsimp [lb]; omega
lemma lb_zero : lb 0=1 := rfl
lemma lb_one : lb 1=1 := rfl
lemma below (x) : x < 2^lb x := Nat.lt_log2_self
lemma above {x:ℕ} (h:0<x) : 2^(lb x) ≤ 2*x := by
unfold lb; rw [pow_succ]
have he : 2^x.log2 ≤ x := Nat.log2_self_le (by omega)
omega
lemma modest {x k : ℕ} (h:x < 2^k) (e:1 ≤ k) : lb x ≤ k := by
by_cases hx : x=0
· simpa [hx,lb_zero]
by_contra! hh
have he : lb x ≥ k+1 := by omega
have ht := le_trans (Nat.pow_le_pow_right (Nat.zero_lt_two) he) (above (x:=x) (by omega))
rw [pow_succ] at ht
omega
lemma growing (x : ℕ) : x+1 ≤ 2^x := by
induction x with
| zero=> simp
| succ x ih=> rw [pow_succ]; omega
lemma lb_le_inc (x : ℕ) : lb x ≤ x+1 :=
modest (lt_of_lt_of_le (show x < (x+1)+1 by omega) (growing _)) (by omega)
lemma lb_mono {x y} (h:x ≤ y) : lb x ≤ lb y:=
modest (h.trans_lt (below _)) (lb_pos y)
lemma lb_succ (x) : lb (x+1) ≤ lb x+1 :=
modest (by have:= below x; rw [pow_succ]; omega) (by omega)
lemma lb_plus (x y) : lb (x+y) ≤ max (lb x) (lb y)+1 := by
apply modest _ (by omega)
have xx := (below x).trans_le (Nat.pow_le_pow_right Nat.zero_lt_two (le_max_left (lb x) (lb y)))
have yy := (below y).trans_le (Nat.pow_le_pow_right Nat.zero_lt_two (le_max_right (lb x) (lb y)))
rw [pow_succ]; omega
lemma lb_times (x y) : lb (x*y) ≤ lb x+lb y :=
modest (by rw [pow_add]; exact Nat.mul_lt_mul_of_lt_of_lt (below x) (below y))
((lb_pos x).trans_le (by omega))
lemma lb_shift (x) : lb (2^x)=x+1 := by
apply le_antisymm
· have ht : 0<(2:ℕ)^x := by positivity
exact modest (by rw [pow_succ]; omega) (by omega)
by_contra! he
have hs:=Nat.pow_le_pow_right (n:=2) Nat.zero_lt_two (show lb (2^x) ≤ x by omega)
have he:=below (2^x); omega
def cord (a s : ℕ) : ℕ := 2^(lb a) * (1+ 2*a +2^(lb a+1)*s)
lemma cord_bounds (a s : ℕ) (hs : 1 ≤ s) :
2 ^ (lb s-1+(2*lb a+1)) ≤ cord a s ∧ cord a s<2^(lb s+ (2*lb a+1)) := by
let k:=lb a
have he1 := (below a)
have he2 := (below s)
have he3 : 2^(lb s-1) ≤ s := by
simp only [lb, Nat.add_sub_cancel]
exact Nat.log2_self_le (by omega)
have he4 (i) : 2^(i+(2*k+1)) = 2^k*(2^(k+1)* (2:ℕ)^i) := by
rw [show i+(2*k+1)=k+((k+1)+i) by omega,pow_add,pow_add]
change 2^(lb s-1+ (2*k+1)) ≤ 2^k*(1+2*a+2^(k+1)*s) ∧
2^k*(1+2*a+2^(k+1)*s) < 2^(lb s+(2*k+1))
simp only [he4]
constructor
· exact Nat.mul_le_mul_left _ ((Nat.mul_le_mul_left (2^(k+1)) he3).trans (by omega))
apply Nat.mul_lt_mul_of_pos_left _ (by positivity)
have he := Nat.mul_le_mul_left (2^(k+1)) (show s+1 ≤ 2^(lb s) from he2)
change a < 2^k at he1
nlinarith [pow_succ (2:ℕ) k]
lemma lb_cord (a s : ℕ) (hs : 1 ≤ s) :
lb (cord a s)=lb s+(2*lb a+1) := by
obtain ⟨ha,hb⟩:=cord_bounds a s hs
apply le_antisymm (modest hb (by omega))
by_contra! h
have h1:=lb_pos s
have h2:=Nat.pow_le_pow_right (n:=2) Nat.zero_lt_two
(show lb (cord a s) ≤ lb s-1+(2*lb a+1) by omega)
have he:=below (cord a s)
omega
lemma cord_fine (a s : ℕ) : s< cord a s ∧ a<cord a s ∧ 1 < cord a s := by
have h : 2 ≤ 2^(lb a):=by
simpa using Nat.pow_le_pow_right (n:=2) Nat.zero_lt_two (lb_pos a)
unfold cord; rw [pow_succ]
have he := Nat.mul_le_mul_right (1+ 2*a +2^lb a*2*s) h
have hz := Nat.mul_le_mul_right s h
refine ⟨?_,?_,?_⟩ <;> nlinarith
def discover (x : ℕ) (k : ℕ) : ℕ :=
forNat (fun j t=> if x % (min (x+1) (2^(j+1)))=0 then j+1 else t) 0 k
def pierce (x : ℕ) := discover x x
def wing (x : ℕ) := min (x+1) (2^pierce x)
def middle (x : ℕ) := x/ wing x /2
def fore (x) := middle x % wing x
def aft (x) := middle x / wing x
lemma pierce_rule (a s : ℕ) : pierce (cord a s)=lb a := by
let k:=lb a
let n:=2^k
let x:=cord a s
let w:=a+n*s
have hn : 0<n := by dsimp [n]; positivity
have hx : x = n*(1+2*w) := by simp only [x,w,n,k,cord,pow_succ]; ring
have hh : n ≤ x := by nlinarith
have hp (j : ℕ) : x%min (x+1) (2^j)=0 ↔ j ≤ k := by
by_cases hg : j ≤ k
· have he : 2^j ∣ x := (pow_dvd_pow _ hg).trans (hx ▸ ⟨_,rfl⟩)
have ht : 2^j ≤ x+1 := by
have h2 : 2^j ≤ n := Nat.pow_le_pow_right Nat.zero_lt_two hg; omega
simp [hg,ht,Nat.mod_eq_zero_of_dvd he]
by_cases ho : 2^j ≤ x+1
· rw [min_eq_right ho]; refine ⟨fun he=>?_,fun e=>by omega⟩
have he1:= (pow_dvd_pow 2 (show k+1 ≤ j by omega)).trans (Nat.dvd_of_mod_eq_zero he)
rw [pow_succ,hx] at he1
obtain ⟨b,hb⟩:=he1
change n*(1+2*w)=n*2*b at hb
rw [mul_assoc] at hb
have ht := Nat.eq_of_mul_eq_mul_left hn hb
omega
rw [min_eq_left (by omega),Nat.mod_eq_of_lt (by omega)]; omega
have hi (j) : discover x j=min j k := by
induction j with
| zero=> simp [discover,forNat]
| succ j ih=>
change (if _ then _ else discover x j)=_
rw [ih]; simp only [hp]
by_cases he:j+1 ≤ k
· simp [he]
have ht:k≤j:=by omega
simp [he,ht,le_trans ht (show j ≤ j+1 by omega)]
have hv:=growing k
change k+1 ≤ n at hv
exact (hi x).trans (by omega)
@[simp] lemma wing_cord (a s) : wing (cord a s)=2^lb a := by
rw [wing,pierce_rule, min_eq_right]
unfold cord
apply le_trans (show _ ≤ 2^lb a*(1+2*a+ 2^(lb a+1)*s) from ?_) (by omega)
exact Nat.le_mul_of_pos_right _ (by omega)
lemma middle_cord (a s) : middle (cord a s)=a+2^(lb a)*s := by
rw [middle,wing_cord,cord,pow_succ]
rw [Nat.mul_div_cancel_left _ (by positivity)]
have he : 1+2*a+2^(lb a)*2*s=1+(a+2^(lb a)*s)*2 :=by ring
rw [he,Nat.add_mul_div_right _ _ (by omega)]
simp
@[simp] lemma fore_cord (a s) : fore (cord a s)=a := by simp [fore,middle_cord,Nat.mod_eq_of_lt (below a)]
@[simp] lemma aft_cord (a s) : aft (cord a s)=s := by
rw [aft,middle_cord,wing_cord,Nat.add_mul_div_left _ _ (by positivity),Nat.div_eq_of_lt (below a),
zero_add]
def bead (a b : ℕ) : ℕ := cord a (b+1)
def heed (n : ℕ) := fore n
def readt (n : ℕ) := aft n-1
@[simp] lemma heed_eq (a b) : heed (bead a b)=a := by simp [heed,bead]
@[simp] lemma read_eq (a b) : readt (bead a b)=b := by simp [readt,bead]
lemma bead_small (a b) : lb (bead a b) ≤ 2*lb a + lb b +2 := by
rw [bead,lb_cord _ _ (by omega)]
have:= lb_succ b; omega
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
open Counter
def hunt (x k : ℕ) := forNat (fun j a=> if min (x+1) (2^(j+1)) ≤ x then j+1 else a) 0 k
lemma under_pow (x j : ℕ) :
min (x+1) (2^(j+1)) ≤ x ↔ j+1 ≤ x.log2 := by
by_cases h:x=0
· subst x
have hs : 1 ≤ (2:ℕ)^(j+1) := Nat.one_le_pow _ _ (by omega)
simp [hs]
have hs : 2^x.log2 ≤ x := Nat.log2_self_le h
have he := below x
unfold lb at he
constructor
· intro hf; have hl : 2^(j+1) ≤ x:=by omega
by_contra! hm
have hg := (Nat.pow_le_pow_right (n:=2) Nat.zero_lt_two (show x.log2+1 ≤ j+1 by omega))
omega
intro hh
have hl : 2^(j+1) ≤ x := le_trans (Nat.pow_le_pow_right Nat.zero_lt_two hh) hs
omega
lemma found (x k) : hunt x k=min k x.log2 := by
induction k with
| zero=> simp [hunt,forNat]
| succ k ih=>
change (if _ then _ else hunt x k)=_
rw [ih]; simp only [under_pow]
by_cases h:k+1≤x.log2
· simp [h]
have he : x.log2≤ k := by omega
simp [h,he,show x.log2≤ k+1 by omega]
variable {f g : NE}
/-- E calculation of a "current or small index" loop -/
lemma run_huntE (f : NE) (p : ℕ→ℕ→Prop) [(x y : ℕ) → Decidable (p x y)]
(hp : ∀ {g j:NE}, E g → E j → Counter.Pick (fun x a => decide (p (g x a) (j x a))))
(h : E f) :
E (fun x a => forNat
(fun j v=> if p (f x a) j then j+1 else v) 0 (f x a)) := by
apply E.iterate (fun x a j v=> if p (f x a) j then j+1 else v) f (fun _ _=>0)
· intro g j hg he
simpa only [decide_eq_true_eq] using (hp h hg).ite hg.succ he
· exact h
· exact E.const 0
· obtain ⟨k,h⟩:=h.1; exact ⟨k,fun x a b e=>by rw [h x a b e]⟩
obtain ⟨d,hp,he⟩:=h.bound
refine ⟨d,hp,fun x a B hb hs j hj=>?_⟩
have hl (j) : forNat (fun j v=> if p (f x a) j then j+1 else v) 0 j ≤ j := by
induction j <;> simp only [forNat]
· exact le_rfl
split <;> omega
exact lt_of_le_of_lt (le_trans (hl j) hj) (he _ _ _ hb hs)
lemma log2E (h:E f) : E (fun x a=> (f x a).log2) := by
have he (n) : hunt n n=n.log2 := (found n n).trans
(min_eq_right (by have he:=lb_le_inc n; unfold lb at he; omega))
simp_rw [← he]
apply run_huntE _ (fun x j=> min (x+1) (2^(j+1)) ≤ x) _ h
intro x j hx hj
have hr := E.capPow (E.const 2) hj.succ hx.succ
convert Pick.test_eq (hr.sub hx) (E.const 0) using 1
ext x a
simp
omega
lemma lbE (h:E f) : E (fun x a=> lb (f x a)) := (log2E h).succ
lemma digitsE (h:E f) : E (fun x a=> 2^lb (f x a)) := by
have he(n) : min (2*(n+1)) (2^lb n)=2^lb n := by
apply min_eq_right
by_cases h:n=0
· subst n; simp [lb_zero]
have he:=above (x:=n) (by omega); omega
simpa only [he] using E.capPow (E.const 2) (lbE h) ((E.const 2).mul h.succ)
lemma cordE (h:E f) (e:E g) : E (fun x a=> cord (f x a) (g x a)) := by
unfold cord; simp_rw [pow_succ]
have ht:=digitsE h
exact ht.mul (((E.const 1).add ((E.const 2).mul h)).add ((ht.mul (E.const 2)).mul e))
lemma pierceE (h:E f) : E (fun x a=> pierce (f x a)) := by
apply run_huntE _ (fun x j=> x%min (x+1) (2^(j+1))=0) _ h
intro x j hx hj
exact Pick.test_eq (hx.mod (E.capPow (E.const 2) hj.succ hx.succ)) (E.const 0)
lemma wingE (h:E f) : E (fun x a=> wing (f x a)) :=
E.capPow (E.const 2) (pierceE h) h.succ
lemma middleE (h:E f) : E (fun x a=> middle (f x a)) := (h.div (wingE h)).div (E.const 2)
lemma foreE (h:E f) : E (fun x a=> fore (f x a)) := (middleE h).mod (wingE h)
lemma aftE (h:E f) : E (fun x a=> aft (f x a)) := (middleE h).div (wingE h)
def Uni (f : Word → ℕ → ℕ) := ∀ ⦃g : NE⦄,E g → E fun x a=> f x (g x a)
class Wire (α:Type) where
enc : α→ℕ
dec : ℕ→α
eq : ∀ a,dec (enc a)=a
tidy : Uni (fun _ i=>enc (dec i))
export Wire (enc dec)
abbrev measure {α} [Wire α] (a : α) := lb (enc a)
instance : Wire ℕ := ⟨id,id,fun _=>rfl,fun _ h=>h⟩
lemma enc_nat (n:ℕ) : enc n=n := rfl
instance {α β} [Wire α] [Wire β] : Wire (α×β) where
enc p:= bead (enc p.1) (enc p.2)
dec i:= (dec (heed i),dec (readt i))
eq p:= by simp [Wire.eq]
tidy:= by
intro g h
have he:= @Wire.tidy α _
have ht:= @Wire.tidy β _
exact cordE (he (foreE h)) (ht (aftE h).pred).succ
instance : Wire Bool where
enc p:= if p then 1 else 0
dec i:= decide (1 ≤ i)
eq p:= by cases p <;> simp
tidy:= by
intro g h
have hg:= E.ite_le (E.const 1) h (E.const 1) (E.const 0)
simpa only [decide_eq_true_eq] using hg
@[simp] lemma dec_round {α} [Wire α] (a : α) : dec (enc a)=a := Wire.eq a
lemma measure_pair {α β} [Wire α] [Wire β] (a : α) (b:β) :
measure (a,b) ≤2*measure a+measure b+2:=bead_small _ _
/-- Pointwise semantic LF functions requiring only wire encodings. -/
abbrev PT (α β : Type) := Word→α→β
def Kn {α β : Type} [Wire α] [Wire β] (f : PT α β) := Uni fun x a => enc (f x (dec a))
namespace Kn
variable {α β γ δ : Type} [Wire α] [Wire β] [Wire γ] [Wire δ]
lemma identity : Kn (fun (_:Word) (x:α)=>x) := Wire.tidy
lemma comp {f:PT α β} {g:PT β γ} (h:Kn g) (e:Kn f) :
Kn (fun x a=> g x (f x a)) := by
intro v hv
simpa only [Wire.eq] using h (e hv)
lemma tuple {f:PT α β} {g:PT α γ} (h:Kn f) (k:Kn g) :
Kn (fun x a=> (f x a,g x a)) := by
intro v hv
exact cordE (h hv) (k hv).succ
lemma first : Kn (fun (_:Word) (x:α×β)=> x.1) := by
intro g h
exact @Wire.tidy α _ _ (foreE h)
lemma next : Kn (fun (_:Word) (x:α×β)=> x.2) := by
intro g h
exact @Wire.tidy β _ _ (aftE h).pred
lemma left {f:PT α (β×γ)} (h:Kn f) : Kn (fun x a=> (f x a).1) := first.comp h
lemma right {f:PT α (β×γ)} (h:Kn f) : Kn (fun x a=> (f x a).2) := next.comp h
lemma wash : Kn (fun (_:Word) (x:α)=>enc x):= Wire.tidy
lemma unpack : Kn (fun (_:Word) (x:ℕ)=> (dec x:α)):= Wire.tidy
lemma fix (b:β) : Kn (fun (_:Word) (_:α)=>b):= fun _ _=> E.const _
lemma word (b : Word→β) (h:E (fun x _=>enc (b x))) :
Kn (fun (x:Word) (_:α)=>b x) := fun _ _=>h
variable {f g t w : PT α ℕ}
lemma add (h:Kn f) (e:Kn g) : Kn (fun x a=> f x a+g x a):=fun _ u=>(h u).add (e u)
lemma sub (h:Kn f) (e:Kn g) : Kn (fun x a=> f x a-g x a):=fun _ u=>(h u).sub (e u)
lemma times (h:Kn f) (e:Kn g) : Kn (fun x a=> f x a*g x a):=fun _ u=>(h u).mul (e u)
lemma div (h:Kn f) (e:Kn g) : Kn (fun x a=> f x a/g x a):=fun _ u=>(h u).div (e u)
lemma mod (h:Kn f) (e:Kn g) : Kn (fun x a=> f x a%g x a):=fun _ u=>(h u).mod (e u)
lemma power (d:ℕ) (h:Kn f) : Kn (fun x a=> (f x a)^d) := fun _ u=>E.pow_const (h u) d
lemma succ (h:Kn f) : Kn (fun x a=> f x a+1):=h.add (fix (α:=α) (1:ℕ))
lemma pred (h:Kn f) : Kn (fun x a=> f x a-1):=h.sub (fix (α:=α) (1:ℕ))
lemma cond {f g:PT α β} {s:PT α Bool} (hs:Kn s) (h:Kn f) (e:Kn g) :
Kn (fun x a=> if s x a then f x a else g x a) := by
intro u hu
convert (hs hu).ite (e hu) (h hu) using 1
ext x a; cases hv:s x (dec (u x a)) <;> simp [Wire.enc,hv]
lemma le (h:Kn f) (e:Kn g) : Kn (fun x a=> decide (f x a ≤ g x a)) := by
intro u hu
have ht:= (h hu).ite_le (e hu) (E.const 1) (E.const 0)
convert ht using 1; ext x a; simp [Wire.enc]
lemma lt (h:Kn f) (e:Kn g) : Kn (fun x a=> decide (f x a < g x a)) :=
h.succ.le e
lemma eq (h:Kn f) (e:Kn g) : Kn (fun x a=> decide (f x a=g x a)) := by
intro u hu
have ht:= (h hu).ite_eq (e hu) (E.const 1) (E.const 0)
convert ht using 1; ext x a; simp [Wire.enc]
lemma cond_le (h:Kn f) (e:Kn g) {u v:PT α β} (hu:Kn u) (hv:Kn v) :
Kn (fun x a=> if f x a ≤ g x a then u x a else v x a) := by
simpa only [decide_eq_true_eq] using (h.le e).cond hu hv
lemma cond_lt (h:Kn f) (e:Kn g) {u v:PT α β} (hu:Kn u) (hv:Kn v) :
Kn (fun x a=> if f x a < g x a then u x a else v x a) := by
simpa only [decide_eq_true_eq] using (h.lt e).cond hu hv
lemma cond_eq (h:Kn f) (e:Kn g) {u v:PT α β} (hu:Kn u) (hv:Kn v) :
Kn (fun x a=> if f x a=g x a then u x a else v x a) := by
simpa only [decide_eq_true_eq] using (h.eq e).cond hu hv
lemma cap (h:Kn t) (k:Kn f) (u:Kn g) :
Kn (fun x a=> min (t x a) ((f x a)^(g x a))) :=
fun _ e=>E.capPow (k e) (u e) (h e)
lemma small (h:Kn f) (k:Kn g) : Kn (fun x a=> min (f x a) (g x a)) :=
fun _ e=>E.minE (h e) (k e)
lemma bl (h:Kn f) : Kn (fun x a=> lb (f x a)) := fun _ e=>lbE (h e)
lemma push (h:Kn f) (k:Kn g) :
Kn (fun x a=> cord (f x a) (g x a)):= fun _ e=>cordE (h e) (k e)
lemma top (h:Kn f) :
Kn (fun x a=> fore (f x a)):= fun _ e=>foreE (h e)
lemma tail (h:Kn f) :
Kn (fun x a=> aft (f x a)):= fun _ e=>aftE (h e)
/-- LF state loops with a uniform numeric ceiling given by another LF expression -/
lemma stroll (step : PT (α×ℕ×ℕ) ℕ)
(n z limit : PT α ℕ)
(h : Kn step) (hn:Kn n) (hz:Kn z) (he:Kn limit)
(hp : ∀ x a,∀ j≤ n x a, forNat (fun k v=>step x (a,k,v)) (z x a) j ≤ limit x a) :
Kn (fun x a=> forNat (fun k v=> step x (a,k,v)) (z x a) (n x a)) := by
intro g hg
let f (x : Word) (a : Store) (j v: ℕ) := step x ((dec (g x a):α), j, v)
apply E.iterate f (fun x a=> n x (dec (g x a))) (fun x a=> z x (dec (g x a)))
· intro j v hj hv
have eu : E (fun x a=> enc ((dec (g x a):α), j x a, v x a)) :=
cordE (@Wire.tidy α _ _ hg) (cordE hj hv.succ).succ
simpa only [Wire.eq,enc_nat,f] using h eu
· exact hn hg
· exact hz hg
· obtain ⟨k,h⟩:=hg.1; exact ⟨k,fun x a b e=>by simp only [f,h x a b e]⟩
obtain ⟨d,hd,h⟩:=(he hg).bound
exact ⟨d,hd,fun x a B e u j v => lt_of_le_of_lt (hp x (dec (g x a)) j v) (h x a B e u)⟩
end Kn
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
open Counter
lemma cord_mono {a b c d} (h:a≤b) (e:c≤d) : cord a c≤cord b d := by
have ht:=lb_mono h
unfold cord; gcongr
lemma bead_mono {a b c d} (h:a≤b) (e:c≤d) : bead a c≤bead b d := cord_mono h (by omega)
lemma pair_mono {a b c d : ℕ} (h:a≤b) (e:c≤d) : enc (a,c)≤enc (b,d):=bead_mono h e
lemma Kn.fold {α β : Type} [Wire α] [Wire β] (step : PT (α× ℕ×β) β)
(z : PT α β) (n lim : PT α ℕ)
(hf: Kn step) (hz:Kn z) (ht:Kn n) (he: Kn lim)
(hh : ∀ x a,∀ j≤ n x a, enc (forNat (fun k v=>step x (a,k,v)) (z x a) j) ≤ lim x a) :
Kn (fun x a=> forNat (fun k v=>step x (a,k,v)) (z x a) (n x a)) := by
let f : PT (α×ℕ×ℕ) ℕ := fun x u=> enc (step x (u.1,u.2.1,dec u.2.2))
have hu(x a j) :
forNat (fun k v=>f x (a,k,v)) (enc (z x a)) j= enc
(forNat (fun k v=>step x (a,k,v)) (z x a) j) := by
induction j <;> simp_all [forNat,f]
have hn : Kn f := wash.comp (hf.comp
(first.tuple (next.left.tuple (unpack.comp next.right))))
have h:= stroll f _ _ _ hn ht (wash.comp hz) he (fun x a j hv=>by rw [hu]; exact hh x a j hv)
simpa only [hu,Wire.eq] using (unpack (α:=β)).comp h
def mesh : List ℕ → ℕ
| []=>1
| a::b=>cord a (mesh b)
lemma mesh_length (l) : l.length < mesh l:=by
induction l with
| nil=>simp [mesh]
| cons a l ih=> exact lt_of_le_of_lt ih (cord_fine a (mesh l)).1
lemma mesh_pos (l) : 1≤ mesh l:= (Nat.zero_le _).trans_lt (mesh_length l)
lemma measure_mesh (a l) : lb (mesh (a::l))=lb (mesh l)+(2*lb a+1) :=
lb_cord _ _ (mesh_pos l)
lemma mesh_append (l r) : lb (mesh (l++r))+1=lb (mesh l)+lb (mesh r) := by
induction l with
| nil=> simp [mesh,lb_one,Nat.add_comm]
| cons v l ih=>
simp only [List.cons_append,measure_mesh]
omega
lemma mesh_reverse (l) : lb (mesh l.reverse)=lb (mesh l) := by
induction l with
| nil=> simp
| cons a l ih=>
rw [List.reverse_cons,measure_mesh]
have ht:=mesh_append l.reverse [a]; rw [measure_mesh,ih] at ht
change _+1=lb (mesh l)+(lb 1+_) at ht; rw [lb_one] at ht
omega
def ebb {α} (f:PT (α×ℕ×ℕ) ℕ) (x : Word) (a : α) (lim load : ℕ) (v:ℕ×ℕ) : ℕ×ℕ :=
if v.1≤1 then v else (min load (aft v.1),min lim (f x (a,fore v.1,v.2)))
def sweep {α} (f:PT (α×ℕ×ℕ) ℕ) (r z lim : PT α ℕ) : PT α ℕ :=
fun x a=>
(forNat (fun _ v=>ebb f x a (lim x a) (r x a) v)
(r x a,min (lim x a) (z x a)) (r x a)).2
lemma Kn.sweepK {α : Type} [Wire α] (f:PT (α×ℕ×ℕ) ℕ) (r z lim : PT α ℕ)
(hf:Kn f) (hr:Kn r) (hz:Kn z) (h:Kn lim) : Kn (sweep f r z lim) := by
let step : PT (α×ℕ×(ℕ×ℕ)) (ℕ×ℕ) := fun x a=> ebb f x a.1 (lim x a.1) (r x a.1) a.2.2
let src : PT α (ℕ×ℕ) := fun x a=>(r x a,min (lim x a) (z x a))
have hv : Kn step := by
have h1 : Kn (fun (_:Word) (a:α×ℕ×(ℕ×ℕ))=> a.1):=first
have ht : Kn (fun (_:Word) (a:α×ℕ×(ℕ×ℕ))=> a.2.2):=next.right
exact ht.left.cond_le (fix 1) ht (((hr.comp h1).small ht.left.tail).tuple
((h.comp h1).small (hf.comp (h1.tuple (ht.left.top.tuple ht.right)))))
have hh : Kn src := hr.tuple (h.small hz)
have he : Kn (fun x a=>enc ((r x a),(lim x a))) := wash.comp (hr.tuple h)
apply right (fold step src r _ hv hh hr he ?_)
intro x a j _
let p:= forNat (fun k v=>step x (a,k,v)) (src x a)
have h1 (j) : (p j).1 ≤ r x a ∧ (p j).2≤ lim x a := by
induction j with
| zero=> exact ⟨le_rfl,min_le_left ..⟩
| succ j ih=>
change (ebb _ _ _ _ _ (p j)).1 ≤ _ ∧ (ebb _ _ _ _ _ (p j)).2 ≤ _
unfold ebb; split
· exact ih
· exact ⟨min_le_left ..,min_le_left ..⟩
exact pair_mono (h1 j).1 (h1 j).2
inductive Scan (lim:ℕ) (g:ℕ→ℕ→ℕ) : ℕ→List ℕ→ℕ→Prop
| nil {x} (h:x≤lim) : Scan lim g x [] x
| cons {x a l y} (h:x≤lim) (e:Scan lim g (g a x) l y) : Scan lim g x (a::l) y
lemma Scan.start {l g a v y} (h:Scan l g a v y) : a≤l := by cases h <;> assumption
lemma forNat_cons {α} (f:α→α) (x : α) (n : ℕ) :
forNat (fun _=>f) x (n+1)=forNat (fun _=>f) (f x) n := by
induction n with
| zero=> rfl
| succ n ih=>
rw [forNat,ih]
rfl
lemma exact_ebb {α} {f:PT (α×ℕ×ℕ) ℕ} {x lim load l a y z}
(h:Scan lim (fun v w=> f x (a,v,w)) z l y) (e:mesh l≤load) (n:ℕ) (hh:l.length≤ n) :
forNat (fun _ v=>ebb f x a lim load v) (mesh l,z) n=(1,y) := by
induction h generalizing n with
| @nil z h=>
induction n with
| zero=> rfl
| succ n ih=>
simp only [forNat,ih (by simp)]
simp [ebb]
| @cons u v l y h g ih=>
cases n with
| zero=> simp at hh
| succ n=>
let a0:=mesh (v::l)
change mesh (v::l)≤ load at e
have he := cord_fine v (mesh l)
have ht : ¬mesh (v::l) ≤ 1 := not_le_of_gt he.2.2
have hh1 : mesh l≤load := he.1.le.trans e
rw [forNat_cons]
change forNat _ (ebb f x a lim load (mesh (v::l),u)) n=_
change ¬cord v (mesh l) ≤ 1 at ht
unfold ebb; simp only [ht,mesh, ↓reduceIte,fore_cord,aft_cord,min_eq_right hh1,min_eq_right g.start]
exact ih hh1 n (by simpa using hh)
lemma exact_sweep {α} {f : PT (α×ℕ×ℕ) ℕ} {r z lim : PT α ℕ} {x a l y}
(h:Scan (lim x a) (fun i j=> f x (a,i,j)) (z x a) l y)
(e:r x a=mesh l) :
sweep f r z lim x a=y := by
unfold sweep; rw [e,min_eq_right h.start]
rw [exact_ebb h le_rfl _ (mesh_length _).le]
def caplen (n:ℕ) := 2^lb n
def windback (_:Word) (n:ℕ) :=
sweep (fun _ (i : ℕ×ℕ×ℕ) => cord i.2.1 i.2.2)
(fun _ k=>k) (fun _ _=>1) (fun _ k=>caplen k) [] n
lemma Kn.caplenK : Kn (fun (_:Word) (n:ℕ)=>caplen n) := fun _ h=>digitsE h
lemma Kn.windbackK : Kn windback :=
sweepK _ _ _ _ (next.left.push next.right) identity (fix 1) caplenK
lemma backscan (l r:List ℕ) (lim) (h:2^lb (mesh (l++r)) ≤ lim) :
Scan lim cord (mesh r) l (mesh (l.reverse++r)) := by
induction l generalizing r with
| nil=>
simp only [List.nil_append,List.reverse_nil]
exact .nil ((below _).le.trans (by simpa using h))
| cons a l ih=>
have he r : lb (mesh l)+lb (mesh r)=lb (mesh (l++r))+1 := (mesh_append l r).symm
have hs : List.reverse (a::l)++r=l.reverse++(a::r) :=by simp
have hu : lb (mesh r) ≤ lb (mesh ((a::l)++r)) := by
simp only [List.cons_append,measure_mesh]
have := he r; have h1:=lb_pos (mesh l); omega
rw [hs]
apply Scan.cons ((below (mesh r)).le.trans ((Nat.pow_le_pow_right Nat.zero_lt_two hu).trans h))
apply ih (a::r)
have hw : lb (mesh (l++a::r))=lb (mesh ((a::l)++r)) := by
have h1:=he (a::r)
rw [measure_mesh] at h1
simp only [List.cons_append,measure_mesh]
have := he r; omega
rw [hw]; exact h
lemma windback_mesh (x) (l:List ℕ) : windback x (mesh l)=mesh l.reverse := by
have h:=backscan l [] (caplen (mesh l)) (by simp [caplen])
exact exact_sweep (by simpa only [List.append_nil,mesh] using h) rfl
end ExactDerandomization.Relay
end
section
/-!
A recursive fixed program interface (only for algorithms whose
space certificates include the suspended calls). The replayed child
query is computed from the caller's tuple and suspended record. In
particular that recipe has **no** access to the caller's shared cursor.
Computed through already uniform functions (LF), charging those as
ephemeral scratch of log magnitude. -/
namespace ExactDerandomization.Relay
open Counter
structure Cub (α β : Type) [Wire α] [Wire β] where
f : PT α β
runs : Kn f
abbrev Site := ℕ×ℕ
abbrev Plot := ℕ×Site
abbrev Slip := ℕ×ℕ
abbrev Drain := Slip × Site
abbrev Flag := Cub Plot Bool
inductive Cog where
| edit (move : Cub Plot Site)
| toss (stem : Cub Slip ℕ) (send : Cub Drain Site)
| seq (p q : Cog)
| bif (cond : Flag) (p q : Cog)
| loop (cond : Flag) (p : Cog)
structure Fare where
limit : ℕ
meter : ℕ→ℕ
def Fare.atm (v:Fare) (q : ℕ) (p : Site) :=
q ≤ v.limit ∧ p.2 ≤ v.limit ∧ lb p.1≤v.meter q
def Fare.pull (v:Fare) (q h q':ℕ) := lb h+1+v.meter q'≤v.meter q
inductive Boots (x:Word) (F:Fare) (main : Cog) :
ℕ → Cog → Site → Site → Prop
| edit {q p a b} : p.f x (q,a)=b → F.atm q a → F.atm q b →
Boots x F main q (.edit p) a b
| toss {q p e a a' b q'} :
p.f x (q,a.1)=q' → e.f x ((q,a.1),a')=b →
F.atm q a → F.atm q b → F.pull q a.1 q' →
Boots x F main q' main (0,a.2) a' →
Boots x F main q (.toss p e) a b
| seq {q p s a b c} : Boots x F main q p a b → Boots x F main q s b c →
Boots x F main q (.seq p s) a c
| yes {q u p s a b} : u.f x (q,a)=true → Boots x F main q p a b →
Boots x F main q (.bif u p s) a b
| no {q u p s a b} : u.f x (q,a)=false → Boots x F main q s a b →
Boots x F main q (.bif u p s) a b
| more {q u p a b c} : u.f x (q,a)=true → Boots x F main q p a b →
Boots x F main q (.loop u p) b c →
Boots x F main q (.loop u p) a c
| lend {q u p a} : u.f x (q,a)=false → F.atm q a →
Boots x F main q (.loop u p) a a
lemma Boots.fits {x F main q p a b} (h:Boots x F main q p a b) :
F.atm q a ∧ F.atm q b:= by induction h <;> grind
inductive Act where
| edit (move : Cub Plot Site) (goal : ℕ)
| fork (u : Flag) (A B : ℕ)
| toss (p : Cub Slip ℕ) (e : Cub Drain Site) (goal : ℕ)
| rest
structure Grid where
slot : ℕ
entry : ℕ
prog : ℕ → Act
low : entry ≤ slot
shut : prog 0=.rest
dome : ∀ i,slot < i → prog i=.rest
namespace Grid
variable (r:Grid)
/-- routes represent synchronous, hence restoring-program-frame execution.
(They need not be cursor-restoring.) -/
inductive Route (r:Grid) (x:Word) (F:Fare) : ℕ→ℕ→Site→ℕ→Site→Prop
| edit {q i a j b f} : r.prog i=.edit f j → f.f x (q,a)=b →
i≤r.slot → j≤r.slot → F.atm q a → F.atm q b → Route r x F q i a j b
| toss {q i a j b q' a' p e} : r.prog i=.toss p e j →
p.f x (q,a.1)=q' → e.f x ((q,a.1),a')=b →
i≤r.slot → j≤r.slot → F.atm q a → F.atm q b → F.pull q a.1 q' →
Route r x F q' r.entry (0,a.2) 0 a' →
Route r x F q i a j b
| fork {q i a j f s t} : r.prog i=.fork f s t → (if f.f x (q,a) then s else t)=j →
i≤r.slot → j≤r.slot → F.atm q a → Route r x F q i a j a
| seq {q i a j b l c} : Route r x F q i a j b → Route r x F q j b l c → Route r x F q i a l c
lemma Route.fits {r x F q i a j b} (h:Route r x F q i a j b) :
i≤r.slot ∧ j≤r.slot ∧ F.atm q a ∧ F.atm q b:= by induction h <;> grind
end Grid
namespace Cog
def Body : Cog→Type
| .edit _| .toss ..=> Unit
| .seq p q=> Body p ⊕ Body q
| .loop _ p=> Unit ⊕ Body p
| .bif _ p q=> Unit ⊕ (Body p ⊕ Body q)
instance (p:Cog) : Finite (Body p):=by
induction p <;>(dsimp only [Body];infer_instance)
def first : (p : Cog) → Body p
| .edit _| .toss ..=>()
| .seq p _=> .inl (first p)
| .loop ..| .bif ..=>.inl ()
def code : (p : Cog) → (Body p → ℕ) → ℕ → Body p → Act
| .edit p,_,t,_=> .edit p t
| .toss p q,_,t,_=> .toss p q t
| .seq p q,f,_,.inl u=>code p (fun i=>f (.inl i)) (f (.inr (first q))) u
| .seq _ q,f,t,.inr u=>code q (fun i=>f (.inr i)) t u
| .loop c p,f,t,.inl _=>.fork c (f (.inr (first p))) t
| .loop _ p,f,_,.inr u=>code p (fun i=>f (.inr i)) (f (.inl ())) u
| .bif c p q,f,_,.inl _=> .fork c (f (.inr (.inl (first p)))) (f (.inr (.inr (first q))))
| .bif _ p _,f,t,.inr (.inl u)=>code p (fun i=> f (.inr (.inl i))) t u
| .bif _ _ q,f,t,.inr (.inr u)=>code q (fun i=> f (.inr (.inr i))) t u
lemma lays {r:Grid} {x F main} (m : Body main→ℕ)
(hl:∀ i,m i≤r.slot) (he : ∀ i,r.prog (m i)=code main m 0 i)
(hs : m (first main)=r.entry)
{q p a b} (h:Boots x F main q p a b) (v:Body p → ℕ) (t:ℕ)
(hu:∀ i,v i≤r.slot) (ht:t≤r.slot) (hh:∀ i,r.prog (v i)=code p v t i) :
r.Route x F q (v (first p)) a t b := by
induction h generalizing t with
| edit e ha hb=> exact .edit (hh _) e (hu _) ht ha hb
| toss u y ha hb h j ih=>
exact .toss (hh _) u y (hu _) ht ha hb h (by rw [← hs]; exact ih m _ hl (Nat.zero_le _) he)
| @seq q p z a b c h1 h2 ih1 ih2=>
exact .seq (ih1 (fun i=> v (Sum.inl i)) _ (fun i=>hu _) (hu (Sum.inr (first z)))
(fun i=>hh (Sum.inl i)))
(ih2 (fun i=>v (Sum.inr i)) t (fun i=>hu _) ht (fun i=>hh (Sum.inr i)))
| @yes q f p z a b e h ih=>
have hh1:= ih (fun i=>v (Sum.inr (Sum.inl i))) t (fun i=>hu _) ht (fun i=>hh (.inr (.inl i)))
exact .seq (.fork (hh _) (ite_eq_left e) (hu _) (hu _) h.fits.1) hh1
| @no q f p z a b e h ih=>
have hh1:= ih (fun i=>v (Sum.inr (Sum.inr i))) t (fun i=>hu _) ht (fun i=>hh (.inr (.inr i)))
exact .seq (.fork (hh _) (ite_eq_right (by simp [e])) (hu _) (hu _) h.fits.1) hh1
| @more q f p a b c e h g ih1 ih2=>
have hh2:= ih1 (fun i=>v (Sum.inr i)) (v (Sum.inl ())) (fun i=>hu _) (hu _)
(fun i=> hh (.inr i))
exact .seq (.fork (hh _) (ite_eq_left e) (hu _) (hu _) h.fits.1) (.seq hh2 (ih2 v t hu ht hh))
| lend e h=> exact .fork (hh _) (ite_eq_right (by simp [e])) (hu _) ht h
lemma room (p:Cog) :
∃ r:Grid, ∀ {x F q a b}, Boots x F p q p a b → r.Route x F q r.entry a 0 b := by
classical
let:=Fintype.ofFinite (Body p)
let e:=Fintype.equivFin (Body p)
let n:=Fintype.card (Body p)
let m : Body p→ℕ :=fun i=> (e i).val+1
let f : ℕ→ Act := fun i=> if h : i<n+1∧i≠0 then code p m 0 (e.symm ⟨i-1,by omega⟩)
else .rest
have hl (i) : m i≤ n := (e i).isLt
let r:Grid:=⟨n,m (first p),f,hl _,by simp [f],fun i hi=> by
exact dite_eq_right (by omega)⟩
have he(i) : f (m i)=code p m 0 i := by
unfold f
have hz : m i<n+1∧m i≠0 := ⟨by have:=hl i; omega,Nat.succ_ne_zero _⟩
rw [dite_eq_left hz]
congr 1; simp [m,e]
exact ⟨r,fun {_ _ _ _ _} h=> lays (r:=r) m hl he rfl h m 0 hl (Nat.zero_le n) he⟩
end Cog
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
open Counter
namespace Grid
variable (r:Grid)
abbrev Motor := ℕ × ℕ × Site
abbrev Hood := ℕ×ℕ
abbrev Carrier := Hood × Motor
/-- which query was invoked from this instruction -/
def fame (x:Word) (a q:ℕ) : ℕ :=
let p : ℕ×ℕ:= dec a
match r.prog p.1 with
| .toss h _ _=>h.f x (q,p.2)
| _=>0
def replay : PT (Hood × ℕ) ℕ :=
sweep (fun x j => r.fame x j.2.1 j.2.2)
(fun x j=>windback x j.2)
(fun _ j=>j.1.2) (fun _ j=>j.1.1)
/-- finite branch selection -/
lemma numerous {α β : Type} [Wire α] [Wire β] (f: Act→ PT α β)
(h:∀ p,Kn (f p)) (n:PT α ℕ) (hn:Kn n) :
Kn (fun x a=> f (r.prog (n x a)) x a) := by
classical
have he(k) :
Kn (fun x a=> if n x a<k then f (r.prog (n x a)) x a else f .rest x a) := by
induction k with
| zero=> simpa using h .rest
| succ k ih=>
convert hn.cond_eq (Kn.fix k) (h (r.prog k)) ih using 1
ext x a
by_cases hn:n x a=k <;> simp [hn] ; grind
convert he (r.slot+1) using 1
ext x a
split
· rfl
· rw [r.dome _ (by omega)]
lemma fameK {α} [Wire α] (h k: PT α ℕ) (hs:Kn h) (he:Kn k) :
Kn (fun x a=> r.fame x (h x a) (k x a)) := by
let p : PT α (ℕ×ℕ):= fun x a=>dec (h x a)
have hp : Kn p := Kn.unpack.comp hs
let f (v:Act) : PT α ℕ:=fun x a=> match v with
| .toss q _ _=> q.f x (k x a,(p x a).2)
| _=>0
apply r.numerous f ?_ _ hp.left
intro j; cases j <;> first| exact Kn.fix _ | next p1 _ _=> exact p1.runs.comp (he.tuple hp.right)
lemma replayK : Kn r.replay := Kn.sweepK _ _ _ _
(r.fameK _ _ Kn.next.left Kn.next.right)
(Kn.windbackK.comp Kn.next) Kn.first.right Kn.first.left
def advance (r:Grid) (op:Act) (x:Word) (a:Carrier) : Motor :=
let q:=r.replay x (a.1,a.2.2.1)
let m:=a.2
match op with
| .edit f i=> (i,m.2.1, f.f x (q,m.2.2))
| .fork f i j=> (if f.f x (q,m.2.2) then i else j,m.2.1,m.2.2)
| .toss ..=> (r.entry,cord (enc (m.1,m.2.2.1)) m.2.1,0,m.2.2.2)
| .rest=>m
def recede (r:Grid) (op:Act) (x:Word) (a:Carrier) : Motor :=
let m:=a.2; let s:=aft m.2.1; let q:=r.replay x (a.1,s)
match op with
| .toss _ e i=> (i,s, e.f x ((q,(dec (fore m.2.1):ℕ×ℕ).2),m.2.2))
| _=>m
def roll (r:Grid) (x:Word) (a:Carrier) : Motor :=
let m:=a.2
if m.1=0 then
if m.2.1≤1 then m else r.recede (r.prog (dec (fore m.2.1):ℕ×ℕ).1) x a
else r.advance (r.prog m.1) x a
lemma rollK : Kn r.roll := by
have h0 : Kn (fun (_:Word) (a: Carrier)=> a.1) := Kn.first
have h1 : Kn (fun (_:Word) (a: Carrier)=> a.2) := Kn.next
have h2 : Kn (fun (_:Word) (a: Carrier)=> a.2.2.1) := h1.right.left
have he : Kn (fun (_:Word) (a: Carrier)=> (dec (fore a.2.2.1):ℕ×ℕ)) :=
Kn.unpack.comp h2.top
apply h1.left.cond_eq (Kn.fix _)
(h2.cond_le (Kn.fix _) h1 (r.numerous r.recede _ _ he.left))
(r.numerous r.advance _ _ h1.left)
· intro p
cases p
· exact h1
· exact h1
· next _ p i => exact (Kn.fix i).tuple (h2.tail.tuple
(p.runs.comp (((r.replayK.comp (h0.tuple h2.tail)).tuple he.right).tuple
h1.right.right)))
· exact h1
intro p
have hx := (r.replayK.comp (h0.tuple h2)).tuple h1.right.right
cases p
· next p i=> exact (Kn.fix i).tuple (h2.tuple (p.runs.comp hx))
· next p i j => exact ((p.runs.comp hx).cond (Kn.fix i) (Kn.fix j)).tuple
(h2.tuple h1.right.right)
· exact (Kn.fix r.entry).tuple
(((Kn.wash.comp (h1.left.tuple h1.right.right.left)).push h2).tuple
((Kn.fix 0).tuple h1.right.right.right))
· exact h1
lemma Scan.snatch {lim f x l q p a} (h:Scan lim f x l q) (hz: f a q=p) (hh:p≤lim) :
Scan lim f x (l++[a]) p := by
induction h
· rw [← hz]; exact .cons (by assumption) (.nil (by omega))
· apply Scan.cons (by assumption); apply_rules
lemma replay_s {x U q0 s q} (h:Scan U (r.fame x) q0 s.reverse q) :
r.replay x ((U,q0),mesh s)=q :=
exact_sweep (l:=s.reverse) h (windback_mesh ..)
lemma parked (x h a) : r.roll x (h,(0,1,a))=(0,1,a):=by simp [roll]
end Grid
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
/-- bounded transitive closure -/
inductive WPath {α} (safe:α→Prop) (g:α→α) : α→α→Prop
| start {x} (h:safe x) : WPath safe g x x
| next {x y z} : safe x → g x=y → WPath safe g y z → WPath safe g x z
lemma WPath.seq {α} {p:α→Prop} {g x y z} (h : WPath p g x y) (e:WPath p g y z): WPath p g x z := by
induction h with | start=> exact e | next h g e ih=> exact .next h g (ih (by assumption))
namespace Grid
variable (r:Grid)
def elbow := 10*(lb r.slot+1)
lemma elbow_hi : 1 ≤ r.elbow := by unfold elbow; omega
def rooms (U : ℕ) := caplen U ^ (10*r.elbow)
abbrev fitsM (U:ℕ) (m:Motor) := enc m ≤ r.rooms U
lemma seats {F : Fare} {U q0 q s i a} (h:lb (mesh s)+r.elbow*F.meter q≤1+r.elbow*F.meter q0)
(ht:i≤r.slot) (hf:F.atm q a)
(hp:2^(F.meter q0) ≤ U) (hs:F.limit ≤ U) :
r.fitsM U (i,mesh s,a) := by
have hu:=lb_mono hp; rw [lb_shift] at hu
have he:= r.elbow_hi
have hm: F.meter q≤F.meter q0 := by
have hz:=mesh_pos s
have hb:=lb_pos (mesh s)
nlinarith
have hey:=lb_mono ht
obtain ⟨ha,hb,hc⟩:=hf
have hec:=lb_mono (hb.trans hs)
have hx:=measure_pair i (mesh s,a)
have hz:=measure_pair (mesh s) a
have hh:=measure_pair a.1 a.2
have hh0:=lb_pos U; have hg:=lb_pos r.slot
change measure a≤2*lb a.1+lb a.2+2 at hh
change measure (i,mesh s,a) ≤ 2*lb i+measure (mesh s,a)+2 at hx
change measure (mesh s,a) ≤ 2*lb (mesh s)+measure a+2 at hz
have hk : measure (i,mesh s,a) ≤ lb U*(10*r.elbow) :=by
unfold elbow at *
nlinarith [Nat.mul_le_mul_right (lb U) (show 1 ≤ lb r.slot from hg),
Nat.mul_le_mul_left (10*(lb r.slot+1)) hu]
exact le_trans (below _).le ((Nat.pow_le_pow_right Nat.zero_lt_two hk).trans_eq (by
unfold rooms caplen; rw [pow_mul]))
lemma extends_by {F : Fare} {q0 q s i a q'} (h:lb (mesh s)+r.elbow*F.meter q≤1+r.elbow*F.meter q0)
(ht:i≤r.slot) (hf:F.pull q a q') :
lb (mesh (enc (i,a)::s))+r.elbow*F.meter q'≤1+r.elbow*F.meter q0 := by
have h2 : lb (enc (i,a)) ≤ 2*lb i+lb a+2:=measure_pair i a
have h3:=lb_mono ht
rw [measure_mesh]
unfold Fare.pull at hf
have hp:=Nat.mul_le_mul_left r.elbow hf
have he:=lb_pos a; have ht1:=lb_pos r.slot
unfold elbow at *
nlinarith
theorem journey {F : Fare} {x q0 U}
(hp:2^(F.meter q0) ≤ U) (hs:F.limit ≤ U)
{q i a j b} (h:r.Route x F q i a j b) {s}
(hh:Scan U (r.fame x) q0 s.reverse q)
(hz:lb (mesh s)+r.elbow*F.meter q≤1+r.elbow*F.meter q0) :
WPath (r.fitsM U) (fun a=> r.roll x ((U,q0),a))
(i,mesh s,a) (j,mesh s,b) := by
induction h generalizing s with
| @edit q i a j b f e l hi hj ha hb=>
refine .next (r.seats hz hi ha hp hs) ?_ (.start (r.seats hz hj hb hp hs))
have hk : i≠0 := fun hv=>by subst i; rw [r.shut] at e; contradiction
simp [roll,advance,hk,e,r.replay_s hh,l]
| @fork q i a j f s' t e l hi hj ha=>
refine .next (r.seats hz hi ha hp hs) ?_ (.start (r.seats hz hj ha hp hs))
have hk : i≠0 := fun hv=>by subst i; rw [r.shut] at e; contradiction
simp [roll,advance,hk,e,r.replay_s hh,l]
| @toss q i a j b q' a' p e he hl hu hi hj ha hb hf hm ih=>
let w:= enc (i,a.1)
have h1 : lb (mesh (w::s))+r.elbow*F.meter q'≤1+r.elbow*F.meter q0 :=r.extends_by hz hi hf
have h2 : Scan U (r.fame x) q0 (w::s).reverse q':=by
rw [List.reverse_cons]
exact Scan.snatch hh (by simp [w,fame,he,hl]) (hm.fits.2.2.1.1.trans hs)
have h3:= ih h2 h1
refine .next (r.seats hz hi ha hp hs) ?_
(h3.seq (.next (r.seats h1 (Nat.zero_le _) hm.fits.2.2.2 hp hs)
?_ (.start (r.seats hz hj hb hp hs))))
· have hk : i≠0 := fun hv=>by subst i; rw [r.shut] at he; contradiction
simp [roll,advance,mesh,hk,he,w]
have he1 : ¬(cord w (mesh s) ≤ 1):= not_le_of_gt (cord_fine ..).2.2
simp only [roll,ite_true,recede,mesh,he1,ite_false,fore_cord,aft_cord,w,dec_round,he,r.replay_s hh,hu]
| seq _ _ ih ig => exact (ih hh hz).seq (ig hh hz)
end Grid
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
open Counter
abbrev hitloop (f : ℕ→ℕ) (x:ℕ) := forNat (fun _=>f) x
lemma conserve {f:ℕ→ℕ} {L z} (h:z≤L) : ∀ n, hitloop (fun i=>min L (f i)) z n≤L := by
intro n; cases n
· exact h
· exact min_le_left ..
lemma forever {f:ℕ→ℕ} {y z : ℕ} (h:f z=z) {j n} (hz:hitloop f y j=z) (hh:j≤ n) :
hitloop f y n=z := by induction n,hh using Nat.le_induction <;> simp_all [hitloop,forNat]
lemma quick {f:ℕ→ℕ} {L x y}
(hh:x≤L) (h:∀ n,f n≤L) (he:f y=y) (hr:∃ j,hitloop f x j=y) :
hitloop f x L=y := by
let j:=Nat.find hr
have hz: hitloop f x j=y:= Nat.find_spec hr
apply forever he hz
have hv : Function.Injective (fun i : Fin (j+1)=>hitloop f x i.val) := by
have hz1 {u v : Fin (j+1)} (ht:u<v) : hitloop f x u.val≠hitloop f x v.val := by
intro hs
have he1 (n:ℕ) : hitloop f x (u.val+n)=hitloop f x (v.val+n) := by
induction n with
| zero=> simpa using hs
| succ n ih=>
unfold hitloop at *; rw [show u.val+(n+1)=u.val+n+1 by omega,
show v.val+(n+1)=v.val+n+1 by omega,forNat,forNat,ih]
have hx:= he1 (j-v.val)
rw [show v.val+(j-v.val)=j by have:=v.isLt; omega,hz] at hx
have hg:j≤u.val+(j-v.val):= Nat.find_min' hr hx
have ht1:=v.isLt; exact (by change u.val < v.val at ht; omega)
intro i v h; rcases lt_trichotomy i v with ht|ht|ht
· exact (hz1 ht h).elim
· exact ht
· exact (hz1 ht h.symm).elim
have hu (n) : hitloop f x n≤L:= by cases n; exact hh; exact h _
let w : Fin (j+1)→ Fin (L+1) := fun i=>⟨_,Nat.lt_succ_of_le (hu i.val)⟩
have he := Fintype.card_le_of_injective w fun i v hz=> hv (congrArg Fin.val hz)
simpa using he
variable {α} [Wire α]
lemma WPath.clipIter {a b:α} {f L} (h:WPath (fun i:α=> enc i≤L) f a b) :
enc a≤L ∧ enc b≤L ∧ ∃ j,hitloop (fun i=> min L (enc (f (dec i)))) (enc a) j=enc b := by
induction h with
| start ha=> exact ⟨ha,ha,0,rfl⟩
| @next a v b ha he h ih=>
obtain ⟨hv,hb,j,hz⟩:=ih
refine ⟨ha,hb,j+1,?_⟩
unfold hitloop; rw [forNat_cons,Wire.eq,he,min_eq_right hv]; exact hz
namespace Grid
variable (r:Grid)
abbrev Job := Hood × Site
def run (r : Grid) : PT Job Site :=
fun x a=>
let L:=r.rooms a.1.1
let z:Motor:= (r.entry,1,a.2)
let n:= hitloop (fun i : ℕ=> min L (enc (r.roll x (a.1,(dec i))))) (min L (enc z)) L
(dec n : Motor).2.2
lemma runK : Kn r.run := by
let L : PT Job ℕ:=fun _ a=>r.rooms a.1.1
have e : Kn L:= Kn.power (10*r.elbow) (Kn.caplenK.comp Kn.first.left)
let z : PT Job Motor :=fun _ a=>(r.entry,1,a.2)
have he: Kn z:= (Kn.fix _).tuple ((Kn.fix _).tuple Kn.next)
let f : PT (Job×ℕ×ℕ) ℕ:= fun x a=> min (L x a.1) (enc (r.roll x (a.1.1,dec a.2.2)))
have ht : Kn f:= (e.comp Kn.first).small
(Kn.wash.comp (r.rollK.comp (Kn.first.left.tuple (Kn.unpack.comp Kn.next.right))))
have hh:= Kn.stroll f L _ L ht e (e.small (Kn.wash.comp he)) e (by
intro x a j _
cases j <;> exact min_le_left _ _)
exact ((Kn.unpack (α:=Motor)).comp hh).right.right
lemma actual {x q F a b U} (ht:r.Route x F q r.entry a 0 b)
(hu : 2^(F.meter q) ≤ U) (hv:F.limit≤U) : r.run x ((U,q),a)=b := by
have hh : Scan U (r.fame x) q ([]:List ℕ) q := .nil (ht.fits.2.2.1.1.trans hv)
have h:= r.journey hu hv ht (s:=[]) hh (by change lb 1+_≤_; rw [lb_one])
obtain ⟨e,f,g⟩:=h.clipIter
change enc (0,(1:ℕ),b)≤_ at f
have he0 : min (r.rooms U) (enc (r.roll x ((U,q),
dec (enc (0,(1:ℕ),b))))) = enc (0,(1:ℕ),b) := by
rw [dec_round,r.parked,min_eq_right f]
have he := quick e (fun i=> min_le_left (r.rooms U) (enc (r.roll x ((U,q),dec i))))
he0 g
unfold run
dsimp only
rw [min_eq_right (show enc (r.entry,(1:ℕ),a) ≤ r.rooms U from e)]
change ((dec (hitloop _ (enc (r.entry,mesh [],a)) (r.rooms U)):Motor).2.2)=b
rw [he,dec_round]
end Grid
/-- Compilation of simultaneous stack certificates. Partial logspace
function extension on all certified executions. -/
theorem realization (main:Cog) : ∃ f : PT Grid.Job Site, Kn f ∧ ∀ {x U F q a b},
2^(F.meter q) ≤ U → F.limit ≤ U → Boots x F main q main a b →
f x ((U,q),a)=b := by
obtain ⟨r,h⟩:=main.room
exact ⟨r.run,r.runK,fun ht he hz=> r.actual (h hz) ht he⟩
lemma Boots.same {F : Fare} {G : Fare} {p x q a b c}
(h:Boots x F p q p a b) (e:Boots x G p q p a c) : b=c := by
obtain ⟨f,_,hf⟩:=realization p
let u:=max (max (2^(F.meter q)) F.limit) (max (2^(G.meter q)) G.limit)
have hp : f x ((u,q),a)=b:=hf (le_trans (le_max_left _ _) (le_max_left _ _)) (le_trans (le_max_right _ _) (le_max_left _ _)) h
have ht : f x ((u,q),a)=c:=hf (le_trans (le_max_left _ _) (le_max_right _ _)) (le_trans (le_max_right _ _) (le_max_right _ _)) e
exact hp.symm.trans ht
end ExactDerandomization.Relay
end
section
/-! A local recipe layer, with spans accounting for numerical clock difference.
The allowance gap pays for both immediate structural information and any
overshoot in requested precision. -/
namespace ExactDerandomization.Relay
open Counter
abbrev span (c d t j x : ℕ) := x+c*j ≤ c*t+c*c*d
abbrev charge (c w t : ℕ):=c*t+c*c*w
lemma movespan {c d t j h e : ℕ} (u:span c d t j h) (hh:d ≤ e) :
span c e t j h:= u.trans (Nat.add_le_add_left (Nat.mul_le_mul_left _ hh) _)
lemma leaner {c d t j x y : ℕ} (h:span c d t j y) (he:x≤y):span c d t j x :=
le_trans (Nat.add_le_add_right he _) h
lemma acock {c d t j x} (h : span c d t j x) (he: 1≤ c) : j ≤ t+c*d:= by
unfold span at h
by_contra! hz; nlinarith
lemma lax {c d t j x} (h:span c d t j x) {D m : ℕ} (he:m*c ≤ D) (hp:1≤c) :
m*x + D*j ≤ D*t+D*c*d := by
obtain ⟨u,hD⟩:=Nat.exists_eq_add_of_le he
have hz:=acock h hp
unfold span at *
have hu:=Nat.mul_le_mul_left u hz
have hw:=Nat.mul_le_mul_left m h
rw [hD]
nlinarith
lemma span_mono {c d t j x} (h:span c d t j x) {D} (he:c ≤ D) (hp:1≤c):
span D d t j x := by
apply le_trans _ (Nat.add_le_add_left (Nat.mul_le_mul_right d (Nat.mul_le_mul_left D he)) (D*t))
simpa only [one_mul] using lax h (m:=1) (by omega) hp
structure Level where
w : ℕ
t : ℕ
/-- fixed syntactic play, prices ignored until the enclosing layer is ready. -/
structure Lot where
x : Word
P : Cog
F : Fare
book : ℕ→Level
namespace Lot
variable (l:Lot)
def state (c : ℕ) (b : Level) (h:Site) :=
h.2 ≤ l.F.limit ∧ span c b.w b.t 0 (lb h.1+1)
def jump (c : ℕ) (b : Level) (d h q:ℕ) :=
let b':=l.book q
b'.w+d ≤ b.w ∧ span c (b.w-b'.w) b.t b'.t (lb h+1)
/-- The clock argument is in b. q is the immutable tuple seen by the
inline recipe (may be virtual, i.e. regenerated via an inline frame). -/
inductive Mane (l:Lot) (c : ℕ) (b : Level) (d : ℕ) (q : ℕ) : Cog→Site→Site→Prop
| edit {p h j} : p.f l.x (q,h)=j → l.state c b h → l.state c b j →
Mane l c b d q (.edit p) h j
| toss {p e a a' u q'} :
p.f l.x (q,a.1)=q' → e.f l.x ((q,a.1),a')=u →
l.state c b a → l.state c b u → l.jump c b d a.1 q' →
Boots l.x l.F l.P q' l.P (0,a.2) a' →
Mane l c b d q (.toss p e) a u
| seq {p s a y u} : Mane l c b d q p a y → Mane l c b d q s y u →
Mane l c b d q (.seq p s) a u
| yes {s u p a y} : s.f l.x (q,a)=true → Mane l c b d q p a y →
Mane l c b d q (.bif s p u) a y
| no {s u p a y} : s.f l.x (q,a)=false → Mane l c b d q u a y →
Mane l c b d q (.bif s p u) a y
| more {s p a y v} : s.f l.x (q,a)=true → Mane l c b d q p a y →
Mane l c b d q (.loop s p) y v → Mane l c b d q (.loop s p) a v
| stop {s p a} : s.f l.x (q,a)=false → l.state c b a → Mane l c b d q (.loop s p) a a
lemma Mane.spots {l c b d q p a y} (h:Mane l c b d q p a y) : l.state c b a ∧ l.state c b y:=
by induction h <;> grind
lemma Mane.mono {l c b d q p a y} (h:Mane l c b d q p a y) {D}
(he:c ≤ D) (hp:1≤c) :
Mane l D b d q p a y := by
have hs {v:Site} (e:l.state c b v) : l.state D b v:=⟨e.1,span_mono e.2 he hp⟩
have ht {v t} (e:l.jump c b d v t) : l.jump D b d v t:=⟨e.1,span_mono e.2 he hp⟩
induction h
· apply Mane.edit (by assumption) (hs ‹_›) (hs ‹_›)
· rename_i q' e f _ _ _ g
exact .toss e f (hs ‹_›) (hs ‹_›) (ht ‹_›) g
· exact .seq (by assumption) (by assumption)
· exact .yes (by assumption) (by assumption)
· exact .no (by assumption) (by assumption)
· exact .more (by assumption) (by assumption) (by assumption)
· exact .stop (by assumption) (hs ‹_›)
theorem Mane.issue {l c b d q p a y} (h:Mane l c b d q p a y) (hb:b=l.book q) (hu:q≤l.F.limit)
(ht : ∀ x, l.F.meter x=charge c (l.book x).w (l.book x).t) :
Boots l.x l.F l.P q p a y:= by
have hs {v:Site} (e:l.state c b v) : l.F.atm q v := by
refine ⟨hu,e.1,?_⟩
rw [ht q,← hb]
obtain ⟨-,he⟩:= e; unfold span charge at *; omega
have he {v t} (e:l.jump c b d v t) : l.F.pull q v t := by
obtain ⟨hz,hu⟩:= e
have hl: (b.w-(l.book t).w)+(l.book t).w=b.w:=by omega
unfold Fare.pull; rw [ht t,ht q,← hb]; unfold span charge at *
nlinarith [congrArg (fun w=> c*c*w) hl]
induction h
· exact .edit (by assumption) (hs ‹_›) (hs ‹_›)
· rename_i q' e f _ _ _ g
exact .toss e f (hs ‹_›) (hs ‹_›) (he ‹_›) g
· exact .seq (by assumption) (by assumption)
· exact .yes (by assumption) (by assumption)
· exact .no (by assumption) (by assumption)
· exact .more (by assumption) (by assumption) (by assumption)
· exact .lend (by assumption) (hs ‹_›)
end Lot
def hold (o:ℕ) (a:Site) : Site := (enc (o,a.1),a.2)
def mark (a:ℕ) := (dec a:ℕ×ℕ).1
def unseat (a:ℕ) := (dec a:ℕ×ℕ).2
lemma marked (o h) : mark (enc (o,(h:ℕ)))=o := by simp [mark]
lemma unseats0 (o h) : unseat (enc ((o:ℕ),h))=(h:ℕ) :=by simp [unseat]
lemma holdcap {c C g o} {a : ℕ} {d t j k : ℕ}
(h:span C d j k (lb a+1)) (e:span c d t j (lb o+1))
(hh:2*c+C≤g) (hc:1≤ c) (hx:1≤ C) :
span g d t k (lb (enc (o,a))+1) := by
have h1:=lax h (m:=1) (show 1*C≤g by omega) hx
have h2:=lax e (m:=2) (show 2*c≤g by omega) hc
have he : lb (enc (o,a)) ≤2*lb o+lb a+2:=measure_pair o a
have hl:= Nat.mul_le_mul_left (g*d) (show C+c≤g by omega)
unfold span
nlinarith
namespace Cog
variable (f:Cub Slip ℕ)
def locate (a:Cub Slip ℕ) : PT Plot Plot :=
fun x p=> (a.f x (p.1,mark p.2.1),unseat p.2.1,p.2.2)
lemma location : Kn (locate f):= by
let p (_:Word) (a:Plot):= (dec a.2.1:ℕ×ℕ)
have ht:Kn p:= Kn.unpack.comp Kn.next.left
exact (f.runs.comp (Kn.first.tuple ht.left)).tuple (ht.right.tuple Kn.next.right)
lemma binds {α} [Wire α] (o:PT α ℕ) (a:PT α Site) (h:Kn o) (e:Kn a) :
Kn (fun x v=> hold (o x v) (a x v)):= (Kn.wash.comp (h.tuple e.left)).tuple e.right
theorem markK {α} [Wire α] {a:PT α ℕ} (e:Kn a) :
Kn (fun x v=> mark (a x v)):= Kn.left ((Kn.unpack (α:=ℕ×ℕ)).comp e)
theorem unseatK {α} [Wire α] {a:PT α ℕ} (e:Kn a) :
Kn (fun x v=> unseat (a x v)):= Kn.right ((Kn.unpack (α:=ℕ×ℕ)).comp e)
def guard0 (p:Flag) : Flag := ⟨fun x a=>p.f x (locate f x a),p.runs.comp (location f)⟩
/-- Inlining carries an inner tuple regenerated from q and the piece o. -/
def focus (v:Cog) : Cog :=
match v with
| .edit p=> .edit ⟨fun x a=> hold (mark a.2.1) (p.f x (locate f x a)),
binds _ _ (markK Kn.next.left) (p.runs.comp (location f))⟩
| .toss p g=> .toss ⟨fun x a=> p.f x (f.f x (a.1,mark a.2),unseat a.2),
p.runs.comp ((f.runs.comp (Kn.first.tuple (markK Kn.next))).tuple (unseatK Kn.next))⟩
⟨fun x a=>let o:=mark a.1.2
hold o (g.f x ((f.f x (a.1.1,o),unseat a.1.2),a.2)),
binds _ _ (markK Kn.first.right) (g.runs.comp
(((f.runs.comp (Kn.first.left.tuple (markK Kn.first.right))).tuple
(unseatK Kn.first.right)).tuple Kn.next))⟩
| .seq q w=>.seq (focus q) (focus w)
| .bif p q w=>.bif (guard0 f p) (focus q) (focus w)
| .loop p q=>.loop (guard0 f p) (focus q)
lemma hitmark {x q o r} (h:f.f x (q,o)=r) (a:Site) :
locate f x (q,hold o a)=(r,a):=by simp [locate,hold,marked,unseats0,h]
lemma focus_word {l c w j d r p a y} (h:Lot.Mane l c ⟨w,j⟩ d r p a y)
{C g o t q} (he:f.f l.x (q,o)=r)
(hr:span C d t j (lb o+1))
(hf:d≤w) (hz:2*C+c≤g) (hc:1≤ c) (hu:1≤ C) :
Lot.Mane l g ⟨w,t⟩ d q (focus f p) (hold o a) (hold o y):= by
have ha {a : Site} (h:l.state c ⟨w,j⟩ a) : l.state g ⟨w,t⟩ (hold o a):=
⟨h.1, holdcap h.2 (movespan hr hf) hz hu hc⟩
have hs {a q} (h:l.jump c ⟨w,j⟩ d a q) : l.jump g ⟨w,t⟩ d (enc (o,a)) q := by
refine ⟨h.1,holdcap h.2 (movespan hr ?_) hz hu hc⟩
have hp :(l.book q).w+d ≤ w:=h.1; dsimp only; omega
induction h
· rename_i e ha1 ha2
apply Lot.Mane.edit _ (ha ha1) (ha ha2)
simp [locate,hold,e,marked,unseats0,he]
· rename_i q' e y1 ha1 ha2 h3 h4
refine Lot.Mane.toss ?_ ?_ (ha ha1) (ha ha2) (hs h3) h4
all_goals simp only [hold,marked,unseats0,he,e,y1]
· exact .seq (by assumption) (by assumption)
· rename_i e h ih
refine .yes ?_ ih; simp only [guard0,hitmark f he,e]
· rename_i e h ih
refine .no ?_ ih; simp only [guard0,hitmark f he,e]
· rename_i e h h' ih ih'
refine .more ?_ ih ih'; simp only [guard0,hitmark f he,e]
· rename_i e h; refine .stop ?_ (ha h); simp only [guard0,hitmark f he,e]
end Cog
end ExactDerandomization.Relay
end
section
namespace ExactDerandomization.Relay
variable {α β : Type} [Wire α] [Wire β]
abbrev Lore (α) := ℕ×α
abbrev Pause (v : α) (c:ℕ) : Site := (enc v,c)
def topNote (f:PT (Lore α) β) (h:Kn f) : Cub Plot Site :=
⟨fun x a=> (enc (f x (a.1, dec a.2.1)),a.2.2),
(Kn.wash.comp (h.comp (Kn.first.tuple (Kn.unpack.comp Kn.next.left)))).tuple Kn.next.right⟩
def etch (f:PT (Lore α) β) (h:Kn f) : Cog := .edit (topNote f h)
def gear (f:PT (Lore α) Bool) (h:Kn f) : Flag :=
⟨fun x a=> f x (a.1, dec a.2.1),h.comp (Kn.first.tuple (Kn.unpack.comp Kn.next.left))⟩
lemma gear_at (f:PT (Lore α) Bool) (h:Kn f) (x q a c) :
(gear f h).f x (q,Pause a c)=f x (q,a) := by simp [gear,Pause]
lemma etches (f:PT (Lore α) β) (h:Kn f) {l : Lot} {c b d q i j w}
(hz:f l.x (q,i)=j) (hv:l.state c b (Pause i w)) (hy:l.state c b (Pause j w)) :
Lot.Mane l c b d q (etch f h) (Pause i w) (Pause j w):=
.edit (by simp [topNote,Pause,hz]) hv hy
lemma Kn.bneg (f:PT α Bool) (h: Kn f) : Kn (fun x a=> !(f x a)) := by
convert h.cond (Kn.fix false) (Kn.fix true) using 1
ext x a
cases he:f x a <;> simp []
end ExactDerandomization.Relay
end
end OAI