noun
elliptic geometry; Riemannian geometry
A branch of non-Euclidean geometry where there are no parallel lines and the sum of angles in a triangle exceeds 180 degrees. Often contrasted with hyperbolic geometry.
楕円幾何学では、三角形の内角の和は180度より大きくなる。
In elliptic geometry, the sum of the interior angles of a triangle is greater than 180 degrees.
Riemann was one of the mathematicians who laid the foundations of elliptic geometry.