Glossary of differential geometry and topology#D

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This is a glossary of terms specific to differential geometry and differential topology. The following three glossaries are closely related:

See also:

Words in italics denote a self-reference to this glossary.

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A

B

  • Bundle – see fiber bundle.
  • Basic element – A basic element x with respect to an element y is an element of a cochain complex (C^*, d) (e.g., complex of differential forms on a manifold) that is closed: dx = 0 and the contraction of x by y is zero.

C

  • Codimension – The codimension of a submanifold is the dimension of the ambient space minus the dimension of the submanifold.

D

  • 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, \pi:E \to B the preimage \pi^{-1}(x) of a point x in the base B is called the fiber over x, often denoted E_x.
  • Frame bundle – the principal bundle of frames on a smooth manifold.

G

H

I

J

L

M

N

  • Neat submanifold – A submanifold whose boundary equals its intersection with the boundary of the manifold into which it is embedded.

O

P

  • Pair of pants – An orientable compact surface with 3 boundary components. All compact orientable surfaces can be reconstructed by gluing pairs of pants along their boundary components.
  • Parallelizable – A smooth manifold is parallelizable if it admits a smooth global frame. This is equivalent to the tangent bundle being trivial.
  • Partition of unity
  • PL-map
  • Principal bundle – A principal bundle is a fiber bundle P \to B together with an action on P by a Lie group G that preserves the fibers of P and acts simply transitively on those fibers.

R

S

  • Submanifold – the image of a smooth embedding of a manifold.
  • Surface – a two-dimensional manifold or submanifold.
  • Systole – least length of a noncontractible loop.

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 T_p(M) and T_p(N) generate the whole tangent space at p of the total manifold.
  • Triangulation

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 \alpha and \beta over the same base B their cartesian product is a vector bundle over B\times B. The diagonal map B\to B\times B induces a vector bundle over B called the Whitney sum of these vector bundles and denoted by \alpha \oplus \beta.
  • Whitney topologies

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Geometry

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Category:Wikipedia glossaries using unordered lists