up:: 021 MOC Algebra
A left- group action of a Group
which satisfies the properties:
- Identity:
- Compatibility:
Right group action
A right- group action is the function
which satisfies the same properties.
Properties
A group action induces an Orbit over a point
Note that Group actions partition a set into its orbits, since their connection via a group element induces an Equivalence Relation.
Also, every point
Properties of group elements from a group action
For any point
Thus, we have that
Types of Group Action
A group action is a Transitive Group Action if it’s a group action which allows transitivity between points in the set.
A group action is said to be a Free Group Action if the only element which stabilizes all elements in