Euclidean -space,
sometimes called Cartesian space or simply -space, is the space of all n-tuples
of real numbers, (, , ..., ). Such -tuples are sometimes called points,
although other nomenclature may be used (see below). The totality of -space is commonly denoted , although older literature uses the symbol (or actually, its non-doublestruck
variant ;
O'Neill 1966, p. 3).