OAI/RepresentationTheory/FoulkesHowe/PlethysmDual.lean
6 declarations, 0 contain sorry, 0 declared as axioms
Lifting perfect duality through a symmetric power
Composition of perfect pairings is separate from construction of the one-level pairing. Supplying the one-level duality charts and their naturality gives the duality and adjoint-action identities for nested symmetric powers.
- def
OAI.Problem346.PlethysmDual.liftDualEquivline 26Source documentation
Lift a perfect-duality chart through a symmetric power using the canonical duality chart for that symmetric power.
def liftDualEquiv (n : ℕ) (e : W ≃ₗ[ℂ] Module.Dual ℂ V) (d : SymPow n (Module.Dual ℂ V) ≃ₗ[ℂ] Module.Dual ℂ (SymPow n V)) : SymPow n W ≃ₗ[ℂ] Module.Dual ℂ (SymPow n V) := …Mentions: OAI.Problem346.SymPow
- theorem
OAI.Problem346.PlethysmDual.liftDualEquiv_adjointline 33Source documentation
Adjointness is preserved when a perfect pairing is lifted through a symmetric power whose duality chart is natural for the given map.
theorem liftDualEquiv_adjoint (n : ℕ) (e : W ≃ₗ[ℂ] Module.Dual ℂ V) (d : SymPow n (Module.Dual ℂ V) ≃ₗ[ℂ] Module.Dual ℂ (SymPow n V)) (A : V →ₗ[ℂ] V) (A' : W →ₗ[ℂ] W) (he : ∀ x y, e (A' x) y = e x (A y)) (hd : ∀ x y, d (symPowMap n A.dualMap x) y = d x (symPowMap n A y)) (x : SymPow n W) (y : SymPow n V) : liftDualEquiv n e d (symPowMap n A' x) y = liftDualEquiv n e d x (symPowMap n A y) := by …Mentions: OAI.Problem346.SymPow, OAI.Problem346.symPowMap, OAI.Problem346.PlethysmDual.liftDualEquiv
- def
OAI.Problem346.PlethysmDual.plethysmDualEquivOfline 56Source documentation
The duality chart for a plethysm is the composite of its inner and outer one-level duality charts.
def plethysmDualEquivOf (outer inner : ℕ) (e : SymPow inner (Module.Dual ℂ V) ≃ₗ[ℂ] Module.Dual ℂ (SymPow inner V)) (d : SymPow outer (Module.Dual ℂ (SymPow inner V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow outer (SymPow inner V))) : SymPow outer (SymPow inner (Module.Dual ℂ V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow outer (SymPow inner V)) := …Mentions: OAI.Problem346.SymPow
- theorem
OAI.Problem346.PlethysmDual.plethysmDualEquivOf_adjointline 67Source documentation
Naturality of each level gives the adjoint-action identity for the plethysm pairing. The dual automorphism here is the ordinary dual map, not the inverse contragredient; this is precisely the adjoint identity.
theorem plethysmDualEquivOf_adjoint (outer inner : ℕ) (e : SymPow inner (Module.Dual ℂ V) ≃ₗ[ℂ] Module.Dual ℂ (SymPow inner V)) (d : SymPow outer (Module.Dual ℂ (SymPow inner V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow outer (SymPow inner V))) (g : V ≃ₗ[ℂ] V) (he : ∀ x y, e (symPowMap inner g.dualMap.toLinearMap x) y = e x (symPowMap inner g.toLinearMap y)) (hd : ∀ x y, d (symPowMap outer (symPowMap inner g.toLinearMap).dualMap x) y = d x (symPowMap outer (symPowMap inner g.toLinearMap) y)) (x : SymPow outer (SymPow inner (Module.Dual ℂ V))) (y : SymPow outer (SymPow inner V)) : …Mentions: OAI.Problem346.SymPow, OAI.Problem346.symPowMap
- theorem
OAI.Problem346.PlethysmDual.exists_embedding_of_dual_surjectionline 88Source documentation
The comparison embedding follows formally from a surjection on the dual vector space and compatible perfect pairings on the two plethysms.
theorem exists_embedding_of_dual_surjection (a b : ℕ) [Module.IsReflexive ℂ (SymPow b (SymPow a V))] [Module.IsReflexive ℂ (SymPow a (SymPow b V))] (e : SymPow b (SymPow a (Module.Dual ℂ V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow b (SymPow a V))) (f : SymPow a (SymPow b (Module.Dual ℂ V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow a (SymPow b V))) (he : ∀ (g : V ≃ₗ[ℂ] V) x y, e (plethysmAction b a g.dualMap x) y = e x (plethysmAction b a g y)) (hf : ∀ (g : V ≃ₗ[ℂ] V) x y, f (plethysmAction a b g.dualMap x) y = f x (plethysmAction a b g y)) (μ : SymPow b (SymPow a (Module.Dual ℂ V)) →ₗ[ℂ] …Mentions: OAI.Problem346.SymPow, OAI.Problem346.plethysmAction
- theorem
OAI.Problem346.PlethysmDual.comparison_of_dual_chartsline 125Source documentation
With finite-dimensionality and canonical-map naturality available, only the two perfect-duality charts and their adjointness remain to construct the comparison embedding from canonical surjectivity on the dual space.
theorem comparison_of_dual_charts (a b : ℕ) [FiniteDimensional ℂ V] (e : SymPow b (SymPow a (Module.Dual ℂ V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow b (SymPow a V))) (f : SymPow a (SymPow b (Module.Dual ℂ V)) ≃ₗ[ℂ] Module.Dual ℂ (SymPow a (SymPow b V))) (he : ∀ (g : V ≃ₗ[ℂ] V) x y, e (plethysmAction b a g.dualMap x) y = e x (plethysmAction b a g y)) (hf : ∀ (g : V ≃ₗ[ℂ] V) x y, f (plethysmAction a b g.dualMap x) y = f x (plethysmAction a b g y)) (hsurj : ∃ μ : SymPow b (SymPow a (Module.Dual ℂ V)) →ₗ[ℂ] SymPow a (SymPow b (Module.Dual ℂ V)), IsFoulkesMap a b (Module.Dual ℂ V) μ ∧ Function.Surjective μ) : …Mentions: OAI.Problem346.SymPow, OAI.Problem346.plethysmAction, OAI.Problem346.IsFoulkesMap