show that they are not equivalent properties. We, then, prove that group strategy-proofness is sufficient for group non …

We define different concepts of group strategy-proofness for social choice functions. We discuss the connections …

their own benefit by declaring false preferences on that domain. Group strategy-proofness is a very attractive requirement … turn out to also satisfy the stronger requirement of group strategy-proofness. This is the case, for example, when … defining domains of preferences guaranteeing that individual and group strategy-proofness are equivalent for all rules defined …

group strategy-proofness. Hence, the equivalence between the two forms of strategy-proofness is due to the underlying common …

properties, which together imply their (partial) group strategy-proofness. This proves that the equivalence between individual … and group strategy-proofness in all these cases is not a fortuitous event, but results from the structure of the functions …