Paired wedges of continuous alternating maps #
This file constructs the paired wedge of continuous alternating maps on real modules with a
topology. Its determinant normalization is the signed-permutation sum divided by the two input
factorials. It provides bilinearity and pullback compatibility for general topological coefficient
spaces, including the flip law, and transports a degree equality in the first factor through the
wedge (ContinuousAlternatingMap.pairedWedge_apply_of_left_eq_smul_cast). A pairing that turns
multiplication by one scalar into multiplication by another, such as a complex-bilinear pairing,
makes the paired wedge semilinear in the same way, and the paired wedge is natural for coefficient
maps intertwining two pairings.
The paired wedge of two alternatizations is the alternatization of the paired product of the
underlying multilinear maps.
Joint continuity of each pairing is supplied explicitly; no norm is required on the domain or
coefficients. The output coefficients require only continuity of multiplication by each fixed
scalar. The flip law assumes this property for the second input coefficient space as well.
It also proves the norm-free interior-product antiderivation law
ι_v (φ ∧ ψ) = ι_v φ ∧ ψ + (-1) ^ (deg φ) • φ ∧ ι_v ψ, using
ContinuousAlternatingMap.curryLeftTopological from the accompanying Curry module.
The normed counterpart is ContinuousAlternatingMap.curryLeft_pairedWedge. Consequently a wedge
α ∧ ψ with a one-form α, evaluated on (u, w) where α kills every vector of w, is the
pairing of α u with ψ w (ContinuousAlternatingMap.pairedWedge_apply_vecCons_of_forall).
The alternating-map API follows Mathlib's AlternatingMap.curryLeft and map_insertNth, and the
paired-wedge design follows Yury Kudryashov's DeRhamCohomology project.
References #
- John M. Lee, Introduction to Smooth Manifolds, 2nd ed., Graduate Texts in Mathematics 218, Springer, 2013, Lemma 14.13.
- Yury Kudryashov's
DeRhamCohomologyproject.
The linear map induced by a continuous bilinear pairing on the tensor product.
Instances For
The pairing-induced linear map evaluates pure tensors by the original pairing.
The unalternated multilinear pairing underlying the paired wedge.
Instances For
The tensor-product construction of the unalternated paired wedge.
Evaluation of the unalternated pairing on concatenated vectors.
The continuous multilinear map associated to the unalternated paired product.
Instances For
Evaluation of the continuous unalternated pairing on concatenated vectors.
The paired wedge of continuous alternating maps, normalized by the two input factorials.
Instances For
The pointwise formula for the paired wedge in all degrees.
Wedge with a degree-zero form is the coefficient pairing with its value on the empty tuple.
On one-forms, the paired wedge is the usual two-term alternating product.
The underlying alternating map of the paired wedge is the alternatization of its unalternated
multilinear pairing, divided by k! l!.
The paired wedge of alternatizations is the alternatization of the paired product: if φ
and ψ are the alternatizations of f and g, then their paired wedge is the alternatization of
v ↦ μ (f (v ∘ Fin.castAdd l)) (g (v ∘ Fin.natAdd k)). The factorials produced by alternatizing
twice cancel the determinant normalization.
Precomposing both inputs of a paired wedge by a continuous linear map is the same as precomposing the resulting wedge.
The paired wedge is additive in its first alternating map.
The paired wedge is additive in its second alternating map.
The paired wedge distributes over finite sums in its first alternating map.
The paired wedge distributes over finite sums in its second alternating map.
If the pairing turns multiplication by c in its first argument into multiplication by d,
then so does the paired wedge in its first alternating map. For a complex-bilinear pairing this is
complex-linearity in the first factor; it also covers pairings that are conjugate-linear in the
first argument.
If the pairing turns multiplication by c in its second argument into multiplication by
d, then so does the paired wedge in its second alternating map. For a complex-bilinear pairing
this is complex-linearity in the second factor.
The paired wedge respects scalar multiplication in its first alternating map.
The paired wedge respects scalar multiplication in its second alternating map.
Degree transport in the first factor of a paired wedge: if A, of degree b, agrees with
c • B after reindexing its arguments along Fin.cast h : Fin a → Fin b, then the wedge of A
and ψ is c • the wedge of B and ψ, evaluated on the correspondingly transported tuple.
The paired wedge is natural in the coefficients: if continuous linear maps L₁, L₂, L
of the coefficient spaces intertwine the pairings μ and μ', then applying L to the paired
wedge of φ and ψ gives the paired wedge of L₁ ∘ φ and L₂ ∘ ψ.
Postcomposing the pairing postcomposes the paired wedge.
The paired wedge is additive in the pairing.
The paired wedge respects scalar multiplication of the pairing.
Negating the pairing negates the paired wedge.
The paired wedge for the zero pairing is zero.
Wedge with the zero form on the left is zero.
Wedge with the zero form on the right is zero.
The flip identity for two pairings that are each other's transpose: swapping the two forms of
a paired wedge swaps the pairing and costs the graded sign (-1) ^ (k * l).
The flip identity: swapping the two forms of a paired wedge flips the pairing and costs the
graded sign (-1) ^ (k * l). This holds for every pairing.
Anticommutation of a paired wedge along a skew-symmetric pairing.
Graded commutativity of the paired wedge along a symmetric pairing.
Wedge with a degree-zero form on the left pairs its value on the empty tuple with the other form.
A wedge α ∧ ψ with a one-form α vanishes on every tuple of vectors that α kills.
The interior product is an antiderivation of degree -1 for the paired wedge:
ι_v (φ ∧ ψ) = ι_v φ ∧ ψ + (-1) ^ (k + 1) • φ ∧ ι_v ψ for a (k + 1)-form φ.
This is the topological counterpart of ContinuousAlternatingMap.curryLeft_pairedWedge and the
formula of Lee, Introduction to Smooth Manifolds, 2nd ed., Lemma 14.13.
Expanding a wedge α ∧ ψ with a one-form α along its first argument u: when α kills the
remaining arguments w, the wedge is μ (α u) (ψ w).