Derivation bundle #
In this file we define the derivations at a point of a manifold on the algebra of smooth fuctions. Moreover, we define the differential of a function in terms of derivations.
The content of this file is not meant to be regarded as an alternative definition to the current tangent bundle but rather as a purely algebraic theory that provides a purely algebraic definition of the Lie algebra for a Lie group.
Equations
- smooth_functions_algebra ๐ I M = smooth_map.algebra
Type synonym, introduced to put a different has_scalar
action on C^nโฎI, M; ๐โฏ
which is defined as f โข r = f(x) * r
.
Equations
Equations
Equations
- pointed_smooth_map.inhabited I = {default := 0}
smooth_map.eval_ring_hom
gives rise to an algebra structure of C^โโฎI, M; ๐โฏ
on ๐
.
Equations
With the eval_algebra
algebra structure evaluation is actually an algebra morphism.
Equations
- pointed_smooth_map.eval x = algebra.of_id C^โคโฎI,M;๐โฏโจxโฉ ๐
The derivations at a point of a manifold. Some regard this as a possible definition of the tangent space
Equations
- point_derivation I x = derivation ๐ C^โคโฎI,M;๐โฏโจxโฉ ๐
Evaluation at a point gives rise to a C^โโฎI, M; ๐โฏ
-linear map between C^โโฎI, M; ๐โฏ
and ๐
.
Equations
The evaluation at a point as a linear map.
Equations
The heterogeneous differential as a linear map. Instead of taking a function as an argument this
differential takes h : f x = y
. It is particularly handy to deal with situations where the points
on where it has to be evaluated are equal but not definitionally equal.
The homogeneous differential as a linear map.