param verboseRules=true.
param verboseRedundant=true.
param verboseCompleted=true.
param verboseEq=true.
param verboseTerm=true.


pred attacker/2. 
pred extend/2.

nounif extend:u,v.
nounif attacker:x,y.

query attacker:u,a[].

reduc
attacker:u,x & extend:u,v -> attacker:v,x.

(* Result:
   Proverif appears to hang during saturation phase; no output.
   Even with "-test".
*)
