Reserve \colon for ("type") signatures

[SomeoneSerge]

The notes currently use, at several places, the \mapsto notation (which is used to define a "value" of the type "function") right after the \colon which is normally followed by a function's signature and can be read, more or less, as \in (assuming that the subsequent \to expression constructs a "type", or a set of appropriate functions).

An example of the offending sentence:

schuller-geometric/ga/12grassmann.tex

Line 49 in d324cd4

&f &\mapsto &\Phi^*(f) := f\circ \phi.

A cleaner alternative:

Or simply:

P.S. This "issue" is not a call to action, but more of a remark. I'm leaving it because I think Frederic Schuller's lectures are a great example of the fine balance between what constitutes a "clear exposition" of a subject, and a "coarse-to-fine" one. The former means that the exposition is rigorous and accurate enough not be confusing, which includes notation. The latter means that (at most times) it's not overwhelming, and gives relevant pieces in a sensible order. These notes can serve an example and it would be only fair if we were to slightly adjust the style