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.
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- 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.
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- 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.
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With the eval_algebra algebra structure evaluation is actually an algebra morphism.
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- 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
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- 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.
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The evaluation at a point as a linear map.
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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.