Let 
be a unitary representation of a group 
on a separable Hilbert
space, and let 
be the smallest weakly closed algebra of bounded linear
operators containing all 
for 
. Then 
is primary if the center of 
consists of only scalar operations.
Primary Representation
See also
Group RepresentationExplore with Wolfram|Alpha
References
Knapp, A. W. "Group Representations and Harmonic Analysis, Part II." Not. Amer. Math. Soc. 43, 537-549, 1996.Referenced on Wolfram|Alpha
Primary RepresentationCite this as:
Weisstein, Eric W. "Primary Representation." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PrimaryRepresentation.html