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LeanPool.RegtsSevenster.RS.Classical.SchurTheory.ColourCycleSum

Discharge of the cycle-type transport hypotheses #

cycleType_permCongr and cycleType_sigmaCongrRight discharge the PermCongrCT and SigmaCT hypotheses: the colour cycle sum and the Frobenius formula for the Jacobi–Trudi character hold unconditionally.

Transport preserves cycle type, discharging the colour cycle sum's hypothesis.

And so does the fibrewise congruence, discharging the Frobenius formula's.

theorem RS.jtChar_frobenius' (μ : YoungDiagram) (t : ℕ → ℂ) :
(↑μ.card.factorial)⁻¹ * ∑ π : Equiv.Perm (Fin μ.card), jtChar μ π * cycleProd t π = diagramSchur μ t

The Frobenius formula for the Jacobi–Trudi character, unconditionally: its normalized cycle-weighted sum is the Jacobi–Trudi determinant.