Interior products of rough differential forms #
Insertion of a vector field into the first slot lowers the degree of a bundle-valued form by
one and squares to zero without further continuity assumptions on the coefficient fibres.
Additivity in the field and the form requires ContinuousAdd on each fibre, scalar laws require
ContinuousConstSMul ℝ, and anticommutation requires IsTopologicalAddGroup.
Pullback commutes with insertion of related fields, also within arbitrary sets.
These operations provide the algebraic input for Cartan's calculus and contraction of volume forms.
We use Mathlib's AlternatingMap.curryLeft and retain continuity of the remaining variables.
This works for arbitrary topological coefficient fibres without choosing fibre norms. For fixed
normed coefficients on the model space it agrees with ContinuousAlternatingMap.curryLeft, and
in the chart at a point it is curryLeft of the coordinate expressions of the form and the field.
Consequently the interior product of a differentiable field and a differentiable form is a
differentiable form, and that of a C^n field and a C^n form is a C^n form.
References #
- John M. Lee, Introduction to Smooth Manifolds, second edition, Chapter 14.
Insert a vector field into the first slot of a rough bundle-valued form. The value bundle is unchanged, and no regularity of the field or the form in the base point is required.
Instances For
Interior product is insertion into the first slot.
At a point, insertion is the topological continuous currying operation.
Insertion of the zero field vanishes.
Insertion into the zero form vanishes.
Interior product is additive in the vector field.
Interior product respects pointwise scalar multiplication of the vector field.
Interior product is additive in the form.
Interior product respects pointwise scalar multiplication of the form.
Inserting the same field twice gives zero.
Interior products by two vector fields anticommute.
Within-set pullback commutes with insertion of fields related by the within-set derivative at the specified point. No differentiability hypothesis is needed beyond this equality.
Pullback commutes with insertion of fields related by the derivative at a point.
Within-set pullback commutes with interior products of related fields.
Pullback commutes with interior products of related fields.
The interior product of a vector field with a fixed-coefficient form.
Instances For
The fixed-coefficient interior product is the corresponding bundle-valued insertion.
Evaluation of the interior product is insertion into the first slot.
Insertion of the zero field vanishes.
The interior product of the zero form vanishes.
Interior product is additive in the vector field.
Interior product respects pointwise scalar multiplication of the vector field.
Interior product distributes over addition of forms.
Interior product respects pointwise scalar multiplication of the form.
Interior product commutes with constant scalar multiplication of forms.
Inserting the same field twice gives zero.
A form vanishes on a field into which it was obtained by insertion: if ι_X ω = α, then
ι_X α = ω(X, X, ...) = 0. For a one-form α and ω = dα this says that a primitive vanishes
on its Liouville field.
Pointwise form of RoughForm.interior_eq_zero_of_interior_eq for one-forms: if ι_X ω = α
for a two-form ω, then α_y(X_y) = 0 at every point y.
Interior products by two vector fields anticommute.
Within-set pullback of a fixed-coefficient interior product, for fields related at a point.
Pullback of a fixed-coefficient interior product, for fields related at a point.
Within-set pullback of a fixed-coefficient interior product, for related fields.
Pullback of a fixed-coefficient interior product, for related fields.
For normed coefficients, the interior product at a point is Mathlib's continuous currying operation applied to the value of the form.
On the model space, the interior product is Mathlib's continuous currying operation.
In the chart at x, the interior product of a form with a vector field is the interior
product of the coordinate expressions of the form and of the field.
The interior product of a vector field and a fixed-coefficient form, both differentiable at a point, is a section of the alternating bundle differentiable at that point.
The interior product of a vector field and a fixed-coefficient form, both C^n at a point, is
a section of the alternating bundle which is C^n at that point.
The interior product of a C^n vector field and a C^n fixed-coefficient form is a C^n
form.