A topic within Geometry, itself one of 11 topics in that field and part of Mathematics.
2 works
Carl Friedrich Gauss
Proves the Theorema Egregium: a surface's curvature can be measured from within the surface itself, without reference to the space it sits in — which is what makes intrinsic geometry possible.
link checked 17 Sept 2026Notes on this copyLuther Pfahler Eisenhart
Develops the geometry of a surface entirely from its first and second fundamental forms, treating Gauss's Theorema Egregium as the fact that curvature is intrinsic and geodesics as the resulting generalisation of a straight line.
link checked 17 Sept 2026Notes on this copy