I have adjusted the first paragraphs (previously a numbered “Definition” – have now made it an “Idea”-section:

Added mentioning of $\mathbb{R}^n$ as an affine space and its original relation as such to Descartes’ “analytic geometry” (“Cartesian geometry”, but we don’t have such an entry yet.)

Removed the suggestion (from rev 13) that one would call any $n$-fold cartesian product, such as of a set $K$, a “Cartesian space”.

]]>