Zappa-Sz\'{e}p product of a Fell bundle and a groupoid

Abstract

We define the Zappa-Sz\'{e}p product of a Fell bundle by a groupoid, which turns out to be a Fell bundle over the Zappa-Sz\'{e}p product of the underlying groupoids. Under certain assumptions, every Fell bundle over the Zappa-Sz\'{e}p product of groupoids arises in this manner. We then study the representation associated with the Zappa-Sz\'{e}p product Fell bundle and show its relation to covariant representations. Finally, we study the associated universal C*-algebra, which turns out to be a C*-blend, generalizing an earlier result about the Zappa-Sz\'{e}p product of groupoid C*-algebras. In the case of discrete groups, the universal C*-algebra of a Fell bundle embeds injectively inside the universal C*-algebra of the Zappa-Sz\'{e}p product Fell bundle.