Wedge products of bundle-valued rough differential forms #
The paired wedge combines two rough forms with values in topological vector-bundle fibres by a continuous bilinear pairing on each fibre. Its formula is the signed permutation sum divided by the two factorials. This construction uses no norm or trivialization on the tangent fibres. Pullback carries both the forms and their pairing to the source manifold. The output fibres need only continuity of multiplication by each fixed scalar. A pairing that turns multiplication by one scalar into multiplication by another, such as a complex-bilinear pairing or a Hermitian metric, makes the wedge semilinear in the same way.
The normalization follows Lee, Introduction to Smooth Manifolds, second edition, Chapter 14.
The algebraic alternatization follows the paired-wedge construction of Yury Kudryashov's
DeRhamCohomology project and Mathlib's MultilinearMap.alternatization.
The paired wedge of rough bundle-valued forms, normalized so that one-forms multiply by the usual two-term alternating product.
Instances For
At each point, the bundle wedge is the paired wedge of the two fibre values.
The fibrewise paired wedge is the signed permutation sum.
On two one-forms, the fibrewise wedge is the usual alternating product.
Swapping the factors of a fibrewise paired wedge flips the pairing and contributes the graded sign. This applies to arbitrary value bundles, with no norm on the tangent fibres or values.
The fibrewise paired wedge is additive in its first form.
The fibrewise paired wedge is additive in its second form.
The fibrewise paired wedge respects scalar multiplication in its first form.
The fibrewise paired wedge respects scalar multiplication in its second form.
If each fibrewise pairing turns multiplication by c in its first argument into
multiplication by d, then so does the fibrewise paired wedge in its first form. This covers
complex-bilinear pairings, and pairings that are conjugate-linear in the first argument, such as
Hermitian metrics.
If each fibrewise pairing turns multiplication by c in its second argument into
multiplication by d, then so does the fibrewise paired wedge in its second form.
The fibrewise paired wedge vanishes when its first form is zero.
The fibrewise paired wedge vanishes when its second form is zero.
Pullback of a paired wedge pulls back its fibrewise pairing as well as both forms.
Within-set pullback likewise commutes with the paired wedge without regularity assumptions.
The paired wedge of fixed-coefficient rough forms. It is the trivial-value-bundle
specialization of bundleWedgeWith.
Instances For
A fixed-coefficient wedge evaluates through the pointwise paired wedge.
Evaluation of the fixed-coefficient paired wedge.
Pairing a rough form with a degree-zero form pairs its value with the function value.
Evaluation of the paired rough-form wedge on two one-forms.
The paired rough-form wedge is additive in its first form.
The paired rough-form wedge is additive in its second form.
The paired rough-form wedge respects scalar multiplication in its first form.
The paired rough-form wedge respects scalar multiplication in its second form.
If the pairing turns multiplication by c in its first argument into multiplication by d,
then so does the paired rough-form wedge in its first form. For a complex-bilinear pairing of
complex coefficient spaces this is complex-linearity in the first form.
If the pairing turns multiplication by c in its second argument into multiplication by
d, then so does the paired rough-form wedge in its second form. For a complex-bilinear pairing
of complex coefficient spaces this is complex-linearity in the second form.
The paired rough-form wedge vanishes when its first form is zero.
The paired rough-form wedge vanishes when its second form is zero.
The paired rough-form wedge is supported in the support of its first form.
The paired rough-form wedge is supported in the support of its second form.
Swapping the factors of a paired rough-form wedge flips the pairing and contributes the graded sign. The argument reindexing is the canonical cast between the two degree sums.
A symmetric fibrewise pairing gives the graded-commutativity identity for rough forms.
The real wedge of rough forms uses multiplication as its fibrewise pairing.
Instances For
The real-valued wedge specializes the paired wedge to multiplication.
Evaluation of the real-valued rough-form wedge in every degree.
Wedging a real-valued rough form with a degree-zero form multiplies its value by the function value.
The wedge of real-valued one-forms has the determinant normalization.
The wedge of the 0-form of a function f with an l-form φ is the pointwise product
f • φ, read in degree 0 + l.
The real wedge is additive in its first form.
The real wedge is additive in its second form.
The real wedge respects scalar multiplication in its first form.
The real wedge respects scalar multiplication in its second form.
The real wedge vanishes when its first form is zero.
The real wedge vanishes when its second form is zero.
Real-valued rough forms commute with the usual graded sign.
Wedging with the 0-form of a function on the right multiplies a form pointwise by the
function.
On a trivial value bundle, the bundle wedge is the fixed-coefficient rough-form wedge.
Within-set pullback preserves the paired wedge of fixed-coefficient rough forms.
Within-set pullback preserves the real-valued rough-form wedge.
Pullback preserves the paired wedge of fixed-coefficient rough forms.
Pullback preserves the real-valued rough-form wedge.