Cayley-Klein's model of dimension-free hyperbolic geometry via projective mappings (Q933712)

Let \((X,\delta)\) be a metric space, where \(X\) is a vector space of dimension free and \(\delta\) is an inner product. In this article the author introduces i) the projective geometry on the projective space of \(X\), and ii) the Klein model of the hyperbolic geometry on a unit disk in \(X\). This article might look like a guide book for undergraduate students. The author argues propositions easily but he quotes some notations and lemmas from another book he wrote, so sometimes we may feel unhelpful in his description.