Category
page 1Differential geometry of surfaces
surface
two-dimensional manifold, and, as such, may be an "abstract surface" not embedded in any Euclidean space
saddle point
stationary point that is not a local extremum
ruled surface
surface through every point of which runs a straight line which equally is on the surface
minimal surface
surface that locally minimizes its area

pseudosphere
In geometry, a pseudosphere is a surface in \mathbb{R}^3. It is the most famous example of a pseudospherical surface. A pseudospherical surface is a surface piecewise smoothly immersed in \mathbb{R}^3 with constant negative Gaussian curvature. A "pseudospherical surface of radius " is a surface in \mathbb{R}^3 having curvature −1/R2 at each point. Its name comes from the analogy with the sphere of radius , which is a surface of curvature 1/R2. Examples include the tractroid, Dini's surfaces, breather surfaces, and the Kuen surface.
Gaussian curvature
product of the principal curvatures of a surface
Theorema Egregium
"Remarkable theorem" about Gauss' curvature as an invariant
principal curvature
at a given point of a surface, one of the two eigenvalues of the shape operator at the point
mean curvature
in differential geometry, an extrinsic measure of curvature of a surface
first fundamental form
second fundamental form
quadratic form related to curvatures of surfaces
Gauss map
in differential geometry, a function that maps each point in a surface to its normal direction
differential geometry of surfaces
deals with the differential geometry of smooth surfaces with various additional structures, most often, a Riemannian metric
Klein quartic
compact Riemann surface of genus 3
Euler's theorem
theorem in the mathematical field of differential geometry
asymptotic curve
concept in differential geometry
Darboux frame
Natural moving frame in differential geometry of surfaces
Macbeath surface
genus-7 Hurwitz surface
Dupin indicatrix
conic section which describes the local shape of a surface

umbilical point
locally spherical point on a mathematical surface
Weingarten equations
equations used in vector calculus

Clairaut's relation
formula in classical differential geometry
Line of greatest slope
steepest slope on a surface
Gauss–Codazzi equations
Fundamental formulas linking the metric and curvature tensor of a manifold
Peano surface