MAYBE
MAYBE
TRS:
 {
     a__if(X1, X2, X3) -> if(X1, X2, X3),
   a__if(true(), X, Y) -> mark(X),
  a__if(false(), X, Y) -> mark(Y),
             mark(c()) -> c(),
            mark(f(X)) -> a__f(mark(X)),
          mark(true()) -> true(),
         mark(false()) -> false(),
  mark(if(X1, X2, X3)) -> a__if(mark(X1), mark(X2), X3),
               a__f(X) -> a__if(mark(X), c(), f(true())),
               a__f(X) -> f(X)
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
       a__if(X1, X2, X3) -> if(X1, X2, X3),
     a__if(true(), X, Y) -> mark(X),
    a__if(false(), X, Y) -> mark(Y),
               mark(c()) -> c(),
              mark(f(X)) -> a__f(mark(X)),
            mark(true()) -> true(),
           mark(false()) -> false(),
    mark(if(X1, X2, X3)) -> a__if(mark(X1), mark(X2), X3),
                 a__f(X) -> a__if(mark(X), c(), f(true())),
                 a__f(X) -> f(X)
   }
  Fail