Group that is a topological space with continuous group action
Algebraic structure → Group theory Group theory
Basic notions
Subgroup
Normal subgroup
Quotient group
(Semi-)direct product
Group homomorphisms
kernel
image
direct sum
wreath product
simple
finite
infinite
continuous
multiplicative
additive
cyclic
abelian
dihedral
nilpotent
solvable
action
Glossary of group theory
List of group theory topics
Finite groups
Cyclic group Zn
Symmetric group Sn
Alternating group An
Dihedral group Dn
Quaternion group Q
Cauchy's theorem
Lagrange's theorem
Sylow theorems
Hall's theorem
p-group
Elementary abelian group
Frobenius group
Schur multiplier
Classification of finite simple groups
cyclic
alternating
Lie type
sporadic
Discrete groups
Lattices
Integers ()
Free group
Modular groups
PSL(2, )
SL(2, )
Arithmetic group
Lattice
Hyperbolic group
Topological and Lie groups
Solenoid
Circle
General linear GL(n)
Special linear SL(n)
Orthogonal O(n)
Euclidean E(n)
Special orthogonal SO(n)
Unitary U(n)
Special unitary SU(n)
Symplectic Sp(n)
G2
F4
E6
E7
E8
Lorentz
Poincaré
Conformal
Diffeomorphism
Loop
Infinite dimensional Lie group
O(∞)
SU(∞)
Sp(∞)
Algebraic groups
Linear algebraic group
Reductive group
Abelian variety
Elliptic curve
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In mathematics, topological groups are the combination of groups and topological spaces, i.e. they are groups and topological spaces at the same time, such that the continuity condition for the group operations connects these two structures together and consequently they are not independent from each other.[1]
Topological groups have been studied extensively in the period of 1925 to 1940. Haar and Weil (respectively in 1933 and 1940) showed that the integrals and Fourier series are special cases of a very wide class of topological groups.[2]
Topological groups, along with continuous group actions, are used to study continuous symmetries, which have many applications, for example, in physics. In functional analysis, every topological vector space is an additive topological group with the additional property that scalar multiplication is continuous; consequently, many results from the theory of topological groups can be applied to functional analysis.
example, in physics. In functional analysis, every topological vector space is an additive topologicalgroup with the additional property that scalar multiplication...
abelian groups Protorus – Mathematical object, a topological abelian group that is compact and connected Ordered topological vector space Topological field –...
mathematical field of algebraic topology, the fundamental group of a topological space is the group of the equivalence classes under homotopy of the loops...
considerations. A topologicalgroup is a locally compact group if the underlying topological space is locally compact and Hausdorff; a topologicalgroup is abelian...
In mathematics, a topological ring is a ring R {\displaystyle R} that is also a topological space such that both the addition and the multiplication are...
homeomorphism group of a topological space is the group consisting of all homeomorphisms from the space to itself with function composition as the group operation...
In mathematics, a topologicalgroup G is called a discrete group if there is no limit point in it (i.e., for each element in G, there is a neighborhood...
addition to continuous actions of topologicalgroups on topological spaces, one also often considers smooth actions of Lie groups on smooth manifolds, regular...
satisfies the above topological definition. Conversely, let G be a topologicalgroup that is a Lie group in the above topological sense and choose an...
onto their images. Every extension of topologicalgroups is therefore a group extension. We say that the topological extensions 0→H→iX→πG→0{\displaystyle...
a compact complete set that is not closed. Any topological vector space is an abelian topologicalgroup under addition, so the above conditions apply....
Poincaré), also called topological isomorphism, or bicontinuous function, is a bijective and continuous function between topological spaces that has a continuous...
compact (topological) group is a topologicalgroup whose topology realizes it as a compact topological space (when an element of the group is operated...
covering group of a topologicalgroup H is a covering space G of H such that G is a topologicalgroup and the covering map p : G → H is a continuous group homomorphism...
infinite abstract groups and topologicalgroups: whenever a group Γ can be realized as a lattice in a topologicalgroup G, the geometry and analysis pertaining...
is a topological space and Y is an additive topologicalgroup (i.e. a group endowed with a topology making its operations continuous). Topological vector...
and related areas of mathematics, a topological property or topological invariant is a property of a topological space that is invariant under homeomorphisms...
well be stated in the context of a topologicalgroup: A sequence ( x k ) {\displaystyle (x_{k})} in a topologicalgroup G {\displaystyle G} is a Cauchy sequence...
representations of the group. As such, they are similar to the group ring associated to a discrete group. If G is a locally compact Hausdorff group, G carries an...
example of a group object is a topologicalgroup, a group whose underlying set is a topological space such that the group operations are continuous. Formally...
Common types of topological spaces include Euclidean spaces, metric spaces and manifolds. Although very general, the concept of topological spaces is fundamental...
h_{1}h_{2}\cdots h_{n}\end{aligned}}} is a topological isomorphism. If a topologicalgroup G {\displaystyle G} is the topological direct sum of the family of subgroups...
circle group has the structure of a topologicalgroup. Moreover, since the unit circle is a closed subset of the complex plane, the circle group is a closed...
disconnected topologicalgroup, there is a unique universal cover of the identity component of the group, and one can take the same cover as topological spaces...
are said to be topological complements in X . {\displaystyle X.} This is true if and only if when considered as additive topologicalgroups (so scalar multiplication...