SKEW PRODUCTS IN THE CENTRALIZER OF COMPACT ABELIAN GROUP EXTENSIONS
G. R. GOODSON
Abstract.
If $T_\psi$ is an ergodic group extension of a weakly mixing transformation $T$ having minimal self-joinings, then it is shown that isomorphism between $T_\psi$ and its inverse implies isomorphism between $T$ and $T^-1$. However, if $T$ satisfies the weaker condition of being simple it is shown that that isomorphism between $T_\psi$ and its inverse does not imply the isomorphism between $T$ and $T^-1$. This answers a question asked by D. Rudolph.
Compressed Postscript 
