Glossary of differential geometry and topology
From Academic Kids
This is a glossary of terms specific to differential geometry and differential topology. The following two glossaries are closely related:
See also:
Words in italics denote a self-reference to this glossary.
| Contents: | top - 0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z |
|---|
A
B
Bundle, see fiber bundle.
C
Codimension. The codimension of a submanifold is the dimension of the ambient space minus the dimension of the submanifold.
Cotangent bundle, the vector bundle of cotangent spaces on a manifold.
D
Diffeomorphism. Given two differentiable manifolds M and N, a bijective map <math>f<math> from M to N is called a diffeomorphism if both <math>f:M\to N<math> and its inverse <math>f^{-1}:N\to M<math> are smooth functions.
Doubling, given a manifold M with boundary, doubling is taking two copies of M and identifying their boundaries. As the result we get a manifold without boundary.
E
F
Fiber. In a fiber bundle, π: E → B the preimage π−1(x) of a point x in the base B is called the fiber over x, often denoted Ex.
Frame
Frame bundle, the principal bundle of frames on a smooth manifold.
Flow
G
H
Hypersurface. A hypersurface is a submanifold of codimension one.
I
L
Lens space. A lens space is a quotient of the 3-sphere (or (2n+1)-sphere) by a free isometric action of Zk.
M
Manifold. A topological manifold is a locally Eulidean Hausdorff space. (In Wikipedia, a manifold need not be paracompact or second-countable.) A Ck manifold is a differentiable manifold whose chart overlap functions are k times continuously differentiable. A C∞ or smooth manifold is a differentiable manifold whose chart overlap functions are infinitely continuously differentiable.
P
Parallelizable. A smooth manifold is parallelizable if it admits a smooth global frame. This is equivalent to the tangent bundle being trivial.
Principal bundle. A principal bundle is a fiber bundle P → B together with right action on P by a Lie group G that preserves the fibers of P and acts simply transitively on those fibers.
S
Submanifold. A submanifold is the image of a smooth embedding of a manifold.
Surface, a two-dimensional manifold or submanifold.
T
Tangent bundle, the vector bundle of tangent spaces on a differentiable manifold.
Tangent field, a section of the tangent bundle. Also called a vector field.
Transversality. Two submanifolds M and N intersect transversally if at each point of intersection p their tangent spaces <math>T_p(M)<math> and <math>T_p(N)<math> generate the whole tangent space at p of the total manifold.
Trivialization
V
Vector bundle, a fiber bundle whose fibers are vector spaces and whose transition functions are linear maps.
Vector field, a section of a vector bundle. More specifically, a vector field can mean a section of the tangent bundle.
W
Whitney sum. A Whitney sum is an analog of the direct product for vector bundles. Given two vector bundles α and β over the same base B their cartesian product is a vector bundle over B ×B. The diagonal map <math>B\to B\times B<math> induces a vector bundle over B called the Whitney sum of these vector bundles and denoted by α⊕β.
