Ciro Santilli @cirosantilli 35

Some cool ones:

A Linear map where the image is the underlying field of the vector space, e.g. ${\mathbb{R}}^n\to \mathbb{R}$.

The set of all linear forms over a vector space forms another vector space called the dual space.

Ciro Santilli's raison d'etre, one of his attempts: OurBigBook.com.

The outcome of closed knowledge is reverse engineering.