A strong motivation for the study of C*-algebras is the theory of unitary represen-
tations of locally compact groups. In the seventies, M. Rieffel and P. Green deve-
loped respectively the theory of induced representations and Mackey normal sub-
group analysis in a C*-algebraic framework. We discuss how Mackey's virtual
groups program also fits into this framework and illustrate it by the example of
projective representations of locally compact abelian groups.
Zoom link for lecture.