Riemannian geometry

Riemannian geometry [rē män′ē ən]

n.

[after G. F. B. Riemann (1826-66), Ger mathematician]

a form of non-Euclidean geometry in which there are no parallel lines, since its figures can be conceived as constructed on a curved surface where all straight lines intersect, and in which the sum of the angles of a triangle exceeds 180°