c V.
|
| It is clear that the composite of two C^p-morphisms is itself
| a C^p-morphism (because it is true for open subsets of vector
| spaces).  The C^p-manifolds and C^p-morphisms form a category.
| The notion of isomorphism is therefore defined ...
|
| If f : X -&gt; Y is a morphism, and (U, q) is a chart
| at a point x in X, while (V, r) is a chart at f(x),
| then we shall also denote by
|
| f_V,U : qU -&gt; rV
|
| the map rfq^-1 [that is, r o f o q^-1].
|
| Lang, DARM, page 22.
|
| It is also convenie