The set of sums 
ranging over a multiplicative group and 
are elements of a field with all
but a finite number of 
.
Group rings are graded algebras.
Group Ring
See also
Graded Algebra, Group AlgebraExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Group Ring." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/GroupRing.html