Category
page 1Differential topology
sphere
A sphere (from Ancient Greek , ) is a surface analogous to the circle, a curve. In solid geometry, a sphere is the set of points that are all at the same distance from a given point in three-dimensional space. That given point is the center of the sphere, and the distance is the sphere's radius. The earliest known mentions of spheres appear in the work of the ancient Greek mathematicians.
tangent
220px|right|thumb|Tangent to a curve. The red line is tangential to the curve at the point marked by a red dot.
220px|right|thumb|Tangent plane to a sphere
vector field
assignment of a vector to each point in a subset of Euclidean space
differential topology
branch of mathematics
implicit function
function defined by a relation of the form 𝑅(𝑥,𝑦)=0, where 𝑅 is a function of several variables and there is a unique 𝑦 that satisfies the relation for every 𝑥
tangent space
vector space associated to a point in a smooth manifold, consisting of vectors tangent to it (in some embedding into Euclidean space)
Gaussian curvature
product of the principal curvatures of a surface
embedding
In mathematics, an embedding (or imbedding) is one instance of some mathematical structure contained within another instance, such as a group that is a subgroup.
tensor field
assignment of a tensor continuously varying across a mathematical space
inverse function theorem
theorem that, if a function is continuously differentiable with nonzero Jacobian determinant at a given point, then it is locally invertible near that point
chain complex
in homological algebra, a structure consisting of a sequence of modules and a sequence of homomorphisms between consecutive modules such that the image of each homomorphism is included in the kernel of the next
tangent bundle
tangent spaces of a manifold considered together

orientability
right|thumb|A torus is an orientable surface
alt=Animation of a flat disk walking on the surface of a Möbius strip, flipping with each revolution.|thumb|The Möbius strip is a non-orientable surface. Note how the disk flips with every loop.
right|thumb|The Roman surface is non-orientable.
immersion
differentiable function whose derivative is everywhere injective
connection
geometrical idea of transporting data along a curve or family of curves in a parallel and consistent manner
Lie derivative
derivative of a tensor field along the flow defined by a vector field
symplectic manifold
in differential geometry, a smooth manifold equipped with a closed, nondegenerate differential 2-form
partition of unity
set of continuous functions from a topological space to the unit interval [0,1] such that for every point x, there is a neighborhood of x where a cofinite number of the functions are 0, and such that the sum of all the function values at x is 1
cobordism
thumb|A cobordism (W; M, N).
In mathematics, cobordism is a fundamental equivalence relation on the class of compact manifolds of the same dimension, set up using the concept of the boundary (French bord, giving cobordism) of a manifold. Two manifolds of the same dimension are cobordant if their disjoint union is the boundary of a compact manifold one dimension higher.
Canonical coordinates
sets of coordinates which can be used to describe a physical system at any given point in time
connected sum
geometric modification on manifolds
cotangent bundle
vector bundle of all cotangent spaces at every point in a manifold

orbifold
alt=Hyperbolic symmetry comparison to Euclidean symmetry|thumb|23star Orbifold Example
In the mathematical disciplines of topology and geometry, an orbifold (for "orbit-manifold") is a generalization of a manifold. Roughly speaking, an orbifold is a topological space that is locally a finite group quotient of a Euclidean space.
Poincaré–Hopf theorem
theorem relating the Euler characteristic of a closed manifold to the number of zeros of a vector field on it
sphere eversion
topological operation of turning a sphere inside-out without creasing

generalized Stokes' theorem
statement about integration of differential forms on manifolds
cotangent space
dual space to the tangent space in differential geometry

Whitney umbrella
three dimensions self-intersecting surface
degree of a continuous mapping
generalization of winding number

section
right inverse of a fiber bundle map
Lie bracket of vector fields
operator in differential topology
normal bundle
vector bundle, complementary to the tangent bundle, associated to an embedding
Pontryagin class
characteristic class defined for real vector bundles
glossary of topology
mathematics glossary
line bundle
one-dimensional vector bundle
submanifold
thumb|160px|Immersed manifold straight line with self-intersections
In mathematics, a submanifold of a manifold M is a subset S which itself has the structure of a manifold, and for which the inclusion map S \rightarrow M satisfies certain properties. There are different types of submanifolds depending on exactly which properties are required. Different authors often have different definitions.
nonholonomic system
system with kinematic constraints that cannot be integrated in position-level constraints
exotic sphere
smooth manifold that is homeomorphic but not diffeomorphic to a sphere
Schoenflies problem
problem in geometric topology
Donaldson theory
Study in mathematical gauge theory
obstruction theory
Mathematical theories
current
contnuous linear functional on the space of compactly supported differential forms
parallelizable manifold
a differentiable manifold whose (co)tangent bundle is topologically trivial
associated bundle
fiber bundle constructed by a representation of a group and a principal bundle
h-cobordism
In geometric topology and differential topology, an (n + 1)-dimensional cobordism W between n-dimensional manifolds M and N is an '''h-cobordism' (the h'' stands for homotopy equivalence) if the inclusion maps
Lie algebroid
infinitesimal version of a Lie groupoid: manifold M with vector bundle E, vector bundle map ρ: E→TM, and a Lie bracket on sections of E, so that [s,ft] = (ρ(s)f)t+f[s,t] for any function f: M→ℝ and sections s, t of E