Duality of Restriction and Induction for $C^*$-Coactions
  Consider a coaction $\delta$ of a locally compact group $G$ on a \cstar algebra $A$, and a closed normal subgroup $N$ of $G$. We prove, following results of Echterhoff for abelian $G$, that Mansfield's imprimitivity between $A\times_{\delta|}G/N$ and $A\times_\delta G\times_{\deltahat,r}N$ implements equivalences between Mansfield induction of representations from $A\times G/N$ to $A\times G$ and restriction of representations from $A\times G\times_r N$ to $A\times G$, and between restriction of representations from $A\times G$ to $A\times G/N$ and Green induction of representations from $A\times G$ to $A\times G\times_r N$. This allows us to deduce properties of Mansfield induction from the known theory of ordinary crossed products. 
S. Kaliszewski (1), John Quigg (Arizona State University), and Iain   Raeburn (1) ((1) University of Newcastle, Australia)