English
For any permutation e, rename e applied to msymm equals msymm with the same μ but indexed by the target set: rename e (msymm σ R μ) = msymm τ R μ.
Русский
Для перестановки e верно: переименование e(mSymm(σ,R,μ)) = msymm(τ,R,μ).
LaTeX
$$$\\text{rename}_{e}(\\mathrm{msymm}_{\\sigma,R}(\\mu)) = \\mathrm{msymm}_{\\tau,R}(\\mu)$$$
Lean4
@[simp]
theorem rename_msymm (μ : n.Partition) (e : σ ≃ τ) : rename e (msymm σ R μ) = msymm τ R μ :=
by
rw [msymm, map_sum]
apply Fintype.sum_equiv (Nat.Partition.ofSymShapeEquiv μ e)
intro
rw [← Multiset.prod_hom, Multiset.map_map, Nat.Partition.ofSymShapeEquiv]
simp