openAI-math-dataset / lean /OAI /Combinatorics /ContingencyTables /Rooted /ForestScaledIdentification.lean
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import OAI.Combinatorics.ContingencyTables.Rooted.ForestScaledPenalty
import OAI.Combinatorics.ContingencyTables.Rooted.ForestPenaltyBound
namespace OAI
/-! # Integer free assignments use the original scaled affine tree values -/
namespace ContingencyTables.ForestScaledPenalty
open scoped BigOperators Classical
open CompanionFactorialApplication GraphCompletionCounts ForestAssignmentSplit
open ForestAffineCoefficients ForestPhysicalCompletion ForestRootPenalty
variable {I J : Type*} [Fintype I] [Fintype J]
lemma free_coefficient_sum (A : Instance I J) (t : TreeCell A.T) (F : I×J → ℝ) :
(∑ f : FreeCell A.small A.T,coefficient A t f.val*F f.val)=
∑ a : I×J,coefficient A t a*F a := by
let p : I×J → Prop := fun a => A.small a.1 a.2=false ∧ ¬A.T.Adj (.inl a.1) (.inr a.2)
calc
_ = ∑ a ∈ Finset.univ.filter p,coefficient A t a*F a :=
(Finset.sum_subtype (p := p) (Finset.univ.filter p) (fun _ => by simp)
(fun a => coefficient A t a*F a)).symm
_ = _ := by
apply Finset.sum_subset (Finset.filter_subset _ _)
intro a _ ha
have hp : ¬p a := by simpa only [Finset.mem_filter,Finset.mem_univ,true_and] using ha
change ¬(A.small a.1 a.2=false ∧ ¬A.T.Adj (.inl a.1) (.inr a.2)) at hp
simp only [coefficient,hp,ite_false,zero_mul]
noncomputable def integerCube (A : Instance I J) (B : ℝ) (f : FreeIndex A.small A.T A.b) :
FreeCell A.small A.T → ℝ := fun a => B*(f a).val/((A.b a.val.1 a.val.2:ℝ)+1)
/-- The scaled affine value at each original integer free assignment is
exactly the manuscript's solved tree value divided by its capacity. -/
theorem scaledTree_integer (A : Instance I J) (B : ℝ) (hB : 0 < B)
(x q : I → J → ℤ) (f : FreeIndex A.small A.T A.b) (t : TreeCell A.T) :
scaledTree A B x q (integerCube A B f) t=
(solved A.small A.T A.r A.c x q
(fun i j => (freeTable A.small A.T A.b f i j:ℤ)) t.val.1 t.val.2:ℝ)/(A.b t.val.1 t.val.2:ℝ) := by
let F : I×J → ℝ := fun a => (freeTable A.small A.T A.b f a.1 a.2:ℝ)
have hterm (a : FreeCell A.small A.T) :
normalizedCoefficient A B t a*integerCube A B f a=
coefficient A t a.val*F a.val/(A.b t.val.1 t.val.2:ℝ) := by
have hN : (A.b a.val.1 a.val.2:ℝ)+1≠0 := by positivity
have hbt : (A.b t.val.1 t.val.2:ℝ)≠0 := by
exact_mod_cast (Nat.ne_of_gt (A.hlarge _ _ (A.hTG t.property)).2)
have hF : F a.val=(f a).val := by
simp [F,freeTable,a.property]
rw [hF]
unfold normalizedCoefficient integerCube
field_simp [hB.ne',hN,hbt]
unfold scaledTree AffinePenalty.affineValue normalizedOffset
simp_rw [hterm]
rw [← Finset.sum_div,free_coefficient_sum,← add_div]
have hh := solved_eq_affine A t x q
(fun i j => (freeTable A.small A.T A.b f i j:ℤ))
unfold affineTree AffinePenalty.affineValue at hh
apply congrArg (fun z : ℝ => z/(A.b t.val.1 t.val.2:ℝ))
simpa only [F,Int.cast_natCast] using hh.symm
lemma intervalCost_div (x b : ℝ) (hb : 0 < b) :
intervalCost (x/b)=max 0 (max (-x) (x-b))/b := by
unfold intervalCost
have he : x/b-1=(x-b)/b := by field_simp [hb.ne']
rw [he,← neg_div, max_div_div_right hb.le]
simpa only [zero_div] using max_div_div_right hb.le (0:ℝ) (max (-x) (x-b))
/-- The root residual in the continuous display is the original root
residual on every integer free assignment; it is independent of those
free values by the proved component-cut cancellation. -/
theorem rootConstant_eq_assignment (A : Instance I J) (x q free : I → J → ℤ) :
rootConstant A x q=
∑ a,if ForestPenaltyApplication.rootFlag A.T a then
|(signedResidual A.small A.T A.r A.c x q free a:ℝ)| else 0 := by
have hroot := root_eq_large A.small A.b A.T A.hTG A.hT A.hmax
(fun i j hs => (A.hlarge i j hs).2)
have hh := signedResidual_independent A.small A.T A.hTG A.r A.c x q free 0 A.X
A.hXr A.hXc hroot
unfold rootConstant
apply Finset.sum_congr rfl
intro a _
rw [hh]
lemma tree_sum_eq (A : Instance I J) (F : I×J → ℝ) :
(∑ t : TreeCell A.T,F t.val)=
∑ i,∑ j,if A.T.Adj (.inl i) (.inr j) then F (i,j) else 0 := by
let p : I×J → Prop := fun a => A.T.Adj (.inl a.1) (.inr a.2)
calc
_ = ∑ a ∈ Finset.univ.filter p,F a :=
(Finset.sum_subtype (p := p) (Finset.univ.filter p) (fun _ => by simp) F).symm
_ = ∑ a : I×J,if p a then F a else 0 := Finset.sum_filter _ _
_ = _ := by rw [Fintype.sum_prod_type]
/-- Thus the continuous display agrees term for term with the actual
root/tree penalty in the original finite definition of h_j. -/
theorem penalty_at_integer (A : Instance I J) (C B : ℝ) (hB : 0 < B)
(z : View A → ℕ) (f : FreeIndex A.small A.T A.b) :
penalty A C B (fun i j => (ForestCountIdentification.smallX A.small z i j:ℤ))
(fun i j => ((A.b i j-ForestCountIdentification.smallY A.small z i j:ℕ):ℤ))
(integerCube A B f)=C*ForestPenaltyBound.penalty A z f := by
let x := ForestCountIdentification.smallX A.small z
let y := ForestCountIdentification.smallY A.small z
let free := freeTable A.small A.T A.b f
let tree := solved A.small A.T A.r A.c (fun i j => (x i j:ℤ))
(fun i j => ((A.b i j-y i j:ℕ):ℤ)) (fun i j => (free i j:ℤ))
have hroot : rootConstant A (fun i j => (x i j:ℤ)) (fun i j => ((A.b i j-y i j:ℕ):ℤ))=
∑ a,if ForestPenaltyApplication.rootFlag A.T a then
|ForestLiteralCount.actualDeviation A.small A.T A.b x y free A.r A.c tree a| else 0 := by
rw [rootConstant_eq_assignment A _ _ (fun i j => (free i j:ℤ))]
apply Finset.sum_congr rfl
intro a _
rw [ForestRootPenalty.abs_actualDeviation_solved]
have htree : (∑ t : TreeCell A.T,intervalCost (scaledTree A B (fun i j => (x i j:ℤ))
(fun i j => ((A.b i j-y i j:ℕ):ℤ)) (integerCube A B f) t))=
∑ i,∑ j,if A.T.Adj (.inl i) (.inr j) then
max 0 (max (-(tree i j:ℝ)) ((tree i j:ℝ)-A.b i j))/(A.b i j:ℝ) else 0 := by
calc
_ = ∑ t : TreeCell A.T,
max 0 (max (-(tree t.val.1 t.val.2:ℝ)) ((tree t.val.1 t.val.2:ℝ)-A.b t.val.1 t.val.2))/
(A.b t.val.1 t.val.2:ℝ) := by
apply Finset.sum_congr rfl
intro t _
rw [scaledTree_integer A B hB]
exact intervalCost_div _ _ (by exact_mod_cast (A.hlarge _ _ (A.hTG t.property)).2)
_ = _ := tree_sum_eq A (fun a =>
max 0 (max (-(tree a.1 a.2:ℝ)) ((tree a.1 a.2:ℝ)-A.b a.1 a.2))/(A.b a.1 a.2:ℝ))
unfold penalty
change C*(rootConstant A (fun i j => (x i j:ℤ)) (fun i j => ((A.b i j-y i j:ℕ):ℤ))+_)=_
rw [hroot,htree]
rfl
end ContingencyTables.ForestScaledPenalty
end OAI