In the
mathematical field of
group theory, a group is residually ''X'' (where ''X'' is some property of groups) if it "can be recovered from groups with property ''X''".
Formally, a group ''G'' is residually ''X'' if for every non-trivial element ''g'' there is a
homomorphism ''h'' from ''G'' to a group with property ''X'' such that
.
More
categorically, a group is residually ''X'' if it embeds into its pro-''X'' completion (see
profinite group In mathematics, a profinite group is a topological group that is in a certain sense assembled from a system of finite groups.
The idea of using a profinite group is to provide a "uniform", or "synoptic", view of an entire system of finite groups. ...
,
pro-p group), that is, the
inverse limit of the
inverse system consisting of all morphisms
from ''G'' to some group ''H'' with property ''X''.
Examples
Important examples include:
*
Residually finite
* Residually
nilpotent
* Residually
solvable
* Residually
free
Free may refer to:
Concept
* Freedom, having the ability to do something, without having to obey anyone/anything
* Freethought, a position that beliefs should be formed only on the basis of logic, reason, and empiricism
* Emancipate, to procur ...
References
*
Infinite group theory
Properties of groups
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