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YoungDiagram.Sigma

noncomputable def Sigma.sigma (X : Chromosome) :

For X ∈ Π, σ(X) is the 2×∞ nonneg integral matrix whose k-th column is (aₖ, bₖ) = sig X^(k), as defined in [Djoković 1982, (15.1)].

Represented as a function ℕ → ℚ × ℚ, where the first component is aₖ and the second is bₖ.

Equations
Instances For
    theorem Sigma.eventually_zero (X : Chromosome) :
    ∃ (K : ), kK, sigma X k = 0
    theorem Sigma.cond_15_2 (X : Chromosome) :
    (∀ (k : ), (sigma X (k + 1)).1 (sigma X k).1) ∃ (K : ), kK, (sigma X k).1 = 0
    theorem Sigma.cond_15_3 (X : Chromosome) :
    (∀ (k : ), (sigma X (k + 1)).2 (sigma X k).2) ∃ (K : ), kK, (sigma X k).2 = 0
    theorem Sigma.cond_15_4 (X : Chromosome) (k : ) :
    if Even k then (sigma X (k + 1)).2 (sigma X k).1 else (sigma X (k + 1)).1 (sigma X k).2

    (15.4) a₀ ≥ b₁ ≥ a₂ ≥ b₃ ≥ …

    theorem Sigma.cond_15_5 (X : Chromosome) (k : ) :
    if Even k then (sigma X (k + 1)).1 (sigma X k).2 else (sigma X (k + 1)).2 (sigma X k).1

    (15.5) b₀ ≥ a₁ ≥ b₂ ≥ a₃ ≥ …

    theorem Sigma.cond_15_6 (X : Chromosome) (k : ) (hX : X Variety.Pi) :
    if Even k then (sigma X (k + 1)).2 - (sigma X (k + 2)).2 (sigma X k).1 - (sigma X (k + 1)).1 else (sigma X (k + 1)).1 - (sigma X (k + 2)).1 (sigma X k).2 - (sigma X (k + 1)).2

    (15.6) a₀ − a₁ ≥ b₁ − b₂ ≥ a₂ − a₃ ≥ b₃ − b₄ ≥ …

    theorem Sigma.cond_15_7 (X : Chromosome) (k : ) (hX : X Variety.Pi) :
    if Even k then (sigma X (k + 1)).1 - (sigma X (k + 2)).1 (sigma X k).2 - (sigma X (k + 1)).2 else (sigma X (k + 1)).2 - (sigma X (k + 2)).2 (sigma X k).1 - (sigma X (k + 1)).1

    (15.7) b₀ − b₁ ≥ a₁ − a₂ ≥ b₂ − b₃ ≥ a₃ − a₄ ≥ …

    theorem Sigma.cond_15_8 {X Y : Variety.Pi} (h : X < Y) (k : ) :
    (sigma (↑X) k).1 (sigma (↑Y) k).1 (sigma (↑X) k).2 (sigma (↑Y) k).2

    (15.8) If X < Y in Π then aₖ ≤ cₖ and bₖ ≤ dₖ for all k, where (aₖ, bₖ) = σ(X)ₖ and (cₖ, dₖ) = σ(Y)ₖ.