MAYBE
MAYBE
TRS:
 {
     a__f(X1, X2, X3) -> f(X1, X2, X3),
    a__f(b(), X, c()) -> a__f(X, a__c(), X),
               a__c() -> b(),
               a__c() -> c(),
            mark(b()) -> b(),
            mark(c()) -> a__c(),
  mark(f(X1, X2, X3)) -> a__f(X1, mark(X2), X3)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
       a__f(X1, X2, X3) -> f(X1, X2, X3),
      a__f(b(), X, c()) -> a__f(X, a__c(), X),
                 a__c() -> b(),
                 a__c() -> c(),
              mark(b()) -> b(),
              mark(c()) -> a__c(),
    mark(f(X1, X2, X3)) -> a__f(X1, mark(X2), X3)
   }
  Fail