Euclid cultural definition

An ancient Greek mathematician; the founder of the study of geometry. Euclid's Elements is the basis for modern school textbooks in geometry. One of the basic statements, or postulates, of Euclid's geometry is that if a line and a point separate from it are given, only one line parallel to the first line can pass through the point.

• Albert Einstein used other approaches to geometry to derive the theory of relativity. These “non-Euclidean geometries” deny Euclid's postulate about parallel lines.