This namespace implements a number of differential operators like [[D]], and
the machinery to apply [[D]] to various structures.

This namespace implements a form field operator and a number of functions for
creating and working with form fields.

A form-field of rank n is an operator that takes n vector fields to a
real-valued function on the manifold. A one-form field takes a single vector
field.

The namespace also contains two definitions of the [[wedge]]
product ([[alt-wedge]] is the second), plus the [[exterior-derivative]].

This namespace implements minimal support for indexed objects and typed
functions.

This namespace defines a functional API for:

- differentiable manifolds (both manifold families like [[Rn]] and manifolds
  specialized to a concrete dimension)
- manifold points
- coordinate patches

As well as a whole bunch of defined manifolds and coordinate systems for
exploration and fun!

Various definitions and utilities for working with maps between manifolds.

This namespace contains vector calculus operators, in versions built on top
of [[derivative/D]] _and_ in Functional Differential Geometry style.

The former transform functions of scalars or vectors, while the latter take a
metric and basis.

This namespace implements a vector field operator and a number of functions for
creating and working with vector fields.

A vector field is an operator that takes a smooth real-valued function of a
manifold and produces a new function on the manifold which computes the
directional derivative of the given function at each point of the manifold.