For a subgroup 
of a group 
, the index of 
, denoted 
, is the cardinal number
of the set of left cosets of 
in 
(which is equal to the cardinal
number of the set of right cosets of 
in 
).
Subgroup Index
See also
Coset, Lagrange's Group Theorem, Left Coset, Right CosetThis entry contributed by Nicolas Bray
Explore with Wolfram|Alpha
Cite this as:
Bray, Nicolas. "Subgroup Index." From MathWorld--A Wolfram Web Resource, created by Eric W. Weisstein. https://mathworld.wolfram.com/SubgroupIndex.html