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teorth/PFR
Source indexedlemma · leanprover/lean4:v4.33.0-rc1

construct_good

PFR.Endgame · PFR/Endgame.lean:417 to 424

Source documentation

If T1,T2,T3T_1, T_2, T_3 are GG-valued random variables with T1+T2+T3=0T_1+T_2+T_3=0 holds identically and

δ:=1i<j3I[Ti;Tj] \delta := \sum_{1 \leq i < j \leq 3} I[T_i;T_j]

Then there exist random variables T1,T2T'_1, T'_2 such that

d[T1;T2]+η(d[X10;T1]d[X10;X1])+η(d[X20;T2]d[X20;X2]) d[T'_1;T'_2] + \eta (d[X_1^0;T'_1] - d[X_1^0;X _1]) + \eta(d[X_2^0;T'_2] - d[X_2^0;X_2])

is at most

(d[X^0_i;T_j] - d[X^0_i; X_i]) \biggr).$$

Exact Lean statement

lemma construct_good :
    k ≤ δ + (p.η/3) * (δ + c[T₁ # T₁] + c[T₂ # T₂] + c[T₃ # T₃])

Complete declaration

Lean source

Canonical source
Full Lean sourceLean 4
lemma construct_good :    k  δ + (p.η/3) *+ c[T₁ # T₁] + c[T₂ # T₂] + c[T₃ # T₃]) := by  have v2 := construct_good_prelim p X₁ X₂ h_min (by rw [ hT]; abel) hT₁ hT₃ hT₂  have v3 := construct_good_prelim p X₁ X₂ h_min (by rw [ hT]; abel) hT₂ hT₁ hT₃  have v6 := construct_good_prelim p X₁ X₂ h_min (by rw [ hT]; abel) hT₃ hT₂ hT₁  simp only [mutualInfo, entropy_comm hT₂ hT₁, entropy_comm hT₃ hT₁, entropy_comm hT₃ hT₂]    at *  linarith