Connected topological group
From Groupprops
This article defines a property that can be evaluated for a topological group (usually, a T0 topological group)
View a complete list of such properties
Contents
Definition
Symbol-free definition
A topological group is termed connected if it satisfies the following equivalent conditions:
- It is connected as a topological space.
- The connected component of the identity element equals the whole group.
Equivalence of definitions
Definitions (1) and (2) are clearly equivalent.
Alternative definition for a locally connected topological group
For a locally connected topological group, being connected is equivalent to having no proper open subgroup. See locally connected and no proper open subgroup implies connected
In particular, this alternate definition applies to algebraic groups equipped with the Zariski topology, as well as to Lie groups. For more, see equivalence of definitions of connected algebraic group and equivalence of definitions of connected Lie group.
Facts
- Connected implies no proper open subgroup: The converse holds for locally connected topological groups.