MAYBE
MAYBE
TRS:
 {
                 mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
                        mark(s(X)) -> active(s(mark(X))),
                mark(cons(X1, X2)) -> active(cons(mark(X1), X2)),
                         mark(0()) -> active(0()),
                       mark(nil()) -> active(nil()),
               mark(first(X1, X2)) -> active(first(mark(X1), mark(X2))),
                     mark(from(X)) -> active(from(mark(X))),
                mark(sel1(X1, X2)) -> active(sel1(mark(X1), mark(X2))),
                    mark(quote(X)) -> active(quote(X)),
                      mark(nil1()) -> active(nil1()),
              mark(first1(X1, X2)) -> active(first1(mark(X1), mark(X2))),
               mark(cons1(X1, X2)) -> active(cons1(mark(X1), mark(X2))),
                        mark(01()) -> active(01()),
                   mark(quote1(X)) -> active(quote1(X)),
                       mark(s1(X)) -> active(s1(mark(X))),
                  mark(unquote(X)) -> active(unquote(mark(X))),
                 mark(unquote1(X)) -> active(unquote1(mark(X))),
               mark(fcons(X1, X2)) -> active(fcons(mark(X1), mark(X2))),
                 sel(X1, mark(X2)) -> sel(X1, X2),
               sel(X1, active(X2)) -> sel(X1, X2),
                 sel(mark(X1), X2) -> sel(X1, X2),
               sel(active(X1), X2) -> sel(X1, X2),
     active(sel(s(X), cons(Y, Z))) -> mark(sel(X, Z)),
      active(sel(0(), cons(X, Z))) -> mark(X),
   active(first(s(X), cons(Y, Z))) -> mark(cons(Y, first(X, Z))),
             active(first(0(), Z)) -> mark(nil()),
                   active(from(X)) -> mark(cons(X, from(s(X)))),
    active(sel1(s(X), cons(Y, Z))) -> mark(sel1(X, Z)),
     active(sel1(0(), cons(X, Z))) -> mark(quote(X)),
          active(quote(sel(X, Z))) -> mark(sel1(X, Z)),
               active(quote(s(X))) -> mark(s1(quote(X))),
                active(quote(0())) -> mark(01()),
  active(first1(s(X), cons(Y, Z))) -> mark(cons1(quote(Y), first1(X, Z))),
            active(first1(0(), Z)) -> mark(nil1()),
        active(quote1(cons(X, Z))) -> mark(cons1(quote(X), quote1(Z))),
             active(quote1(nil())) -> mark(nil1()),
       active(quote1(first(X, Z))) -> mark(first1(X, Z)),
             active(unquote(01())) -> mark(0()),
            active(unquote(s1(X))) -> mark(s(unquote(X))),
          active(unquote1(nil1())) -> mark(nil()),
     active(unquote1(cons1(X, Z))) -> mark(fcons(unquote(X), unquote1(Z))),
               active(fcons(X, Z)) -> mark(cons(X, Z)),
                        s(mark(X)) -> s(X),
                      s(active(X)) -> s(X),
                cons(X1, mark(X2)) -> cons(X1, X2),
              cons(X1, active(X2)) -> cons(X1, X2),
                cons(mark(X1), X2) -> cons(X1, X2),
              cons(active(X1), X2) -> cons(X1, X2),
               first(X1, mark(X2)) -> first(X1, X2),
             first(X1, active(X2)) -> first(X1, X2),
               first(mark(X1), X2) -> first(X1, X2),
             first(active(X1), X2) -> first(X1, X2),
                     from(mark(X)) -> from(X),
                   from(active(X)) -> from(X),
                sel1(X1, mark(X2)) -> sel1(X1, X2),
              sel1(X1, active(X2)) -> sel1(X1, X2),
                sel1(mark(X1), X2) -> sel1(X1, X2),
              sel1(active(X1), X2) -> sel1(X1, X2),
                    quote(mark(X)) -> quote(X),
                  quote(active(X)) -> quote(X),
              first1(X1, mark(X2)) -> first1(X1, X2),
            first1(X1, active(X2)) -> first1(X1, X2),
              first1(mark(X1), X2) -> first1(X1, X2),
            first1(active(X1), X2) -> first1(X1, X2),
               cons1(X1, mark(X2)) -> cons1(X1, X2),
             cons1(X1, active(X2)) -> cons1(X1, X2),
               cons1(mark(X1), X2) -> cons1(X1, X2),
             cons1(active(X1), X2) -> cons1(X1, X2),
                   quote1(mark(X)) -> quote1(X),
                 quote1(active(X)) -> quote1(X),
                       s1(mark(X)) -> s1(X),
                     s1(active(X)) -> s1(X),
                  unquote(mark(X)) -> unquote(X),
                unquote(active(X)) -> unquote(X),
                 unquote1(mark(X)) -> unquote1(X),
               unquote1(active(X)) -> unquote1(X),
               fcons(X1, mark(X2)) -> fcons(X1, X2),
             fcons(X1, active(X2)) -> fcons(X1, X2),
               fcons(mark(X1), X2) -> fcons(X1, X2),
             fcons(active(X1), X2) -> fcons(X1, X2)
 }
 DUP: We consider a duplicating system.
  Trs:
   {
                   mark(sel(X1, X2)) -> active(sel(mark(X1), mark(X2))),
                          mark(s(X)) -> active(s(mark(X))),
                  mark(cons(X1, X2)) -> active(cons(mark(X1), X2)),
                           mark(0()) -> active(0()),
                         mark(nil()) -> active(nil()),
                 mark(first(X1, X2)) -> active(first(mark(X1), mark(X2))),
                       mark(from(X)) -> active(from(mark(X))),
                  mark(sel1(X1, X2)) -> active(sel1(mark(X1), mark(X2))),
                      mark(quote(X)) -> active(quote(X)),
                        mark(nil1()) -> active(nil1()),
                mark(first1(X1, X2)) -> active(first1(mark(X1), mark(X2))),
                 mark(cons1(X1, X2)) -> active(cons1(mark(X1), mark(X2))),
                          mark(01()) -> active(01()),
                     mark(quote1(X)) -> active(quote1(X)),
                         mark(s1(X)) -> active(s1(mark(X))),
                    mark(unquote(X)) -> active(unquote(mark(X))),
                   mark(unquote1(X)) -> active(unquote1(mark(X))),
                 mark(fcons(X1, X2)) -> active(fcons(mark(X1), mark(X2))),
                   sel(X1, mark(X2)) -> sel(X1, X2),
                 sel(X1, active(X2)) -> sel(X1, X2),
                   sel(mark(X1), X2) -> sel(X1, X2),
                 sel(active(X1), X2) -> sel(X1, X2),
       active(sel(s(X), cons(Y, Z))) -> mark(sel(X, Z)),
        active(sel(0(), cons(X, Z))) -> mark(X),
     active(first(s(X), cons(Y, Z))) -> mark(cons(Y, first(X, Z))),
               active(first(0(), Z)) -> mark(nil()),
                     active(from(X)) -> mark(cons(X, from(s(X)))),
      active(sel1(s(X), cons(Y, Z))) -> mark(sel1(X, Z)),
       active(sel1(0(), cons(X, Z))) -> mark(quote(X)),
            active(quote(sel(X, Z))) -> mark(sel1(X, Z)),
                 active(quote(s(X))) -> mark(s1(quote(X))),
                  active(quote(0())) -> mark(01()),
    active(first1(s(X), cons(Y, Z))) -> mark(cons1(quote(Y), first1(X, Z))),
              active(first1(0(), Z)) -> mark(nil1()),
          active(quote1(cons(X, Z))) -> mark(cons1(quote(X), quote1(Z))),
               active(quote1(nil())) -> mark(nil1()),
         active(quote1(first(X, Z))) -> mark(first1(X, Z)),
               active(unquote(01())) -> mark(0()),
              active(unquote(s1(X))) -> mark(s(unquote(X))),
            active(unquote1(nil1())) -> mark(nil()),
       active(unquote1(cons1(X, Z))) -> mark(fcons(unquote(X), unquote1(Z))),
                 active(fcons(X, Z)) -> mark(cons(X, Z)),
                          s(mark(X)) -> s(X),
                        s(active(X)) -> s(X),
                  cons(X1, mark(X2)) -> cons(X1, X2),
                cons(X1, active(X2)) -> cons(X1, X2),
                  cons(mark(X1), X2) -> cons(X1, X2),
                cons(active(X1), X2) -> cons(X1, X2),
                 first(X1, mark(X2)) -> first(X1, X2),
               first(X1, active(X2)) -> first(X1, X2),
                 first(mark(X1), X2) -> first(X1, X2),
               first(active(X1), X2) -> first(X1, X2),
                       from(mark(X)) -> from(X),
                     from(active(X)) -> from(X),
                  sel1(X1, mark(X2)) -> sel1(X1, X2),
                sel1(X1, active(X2)) -> sel1(X1, X2),
                  sel1(mark(X1), X2) -> sel1(X1, X2),
                sel1(active(X1), X2) -> sel1(X1, X2),
                      quote(mark(X)) -> quote(X),
                    quote(active(X)) -> quote(X),
                first1(X1, mark(X2)) -> first1(X1, X2),
              first1(X1, active(X2)) -> first1(X1, X2),
                first1(mark(X1), X2) -> first1(X1, X2),
              first1(active(X1), X2) -> first1(X1, X2),
                 cons1(X1, mark(X2)) -> cons1(X1, X2),
               cons1(X1, active(X2)) -> cons1(X1, X2),
                 cons1(mark(X1), X2) -> cons1(X1, X2),
               cons1(active(X1), X2) -> cons1(X1, X2),
                     quote1(mark(X)) -> quote1(X),
                   quote1(active(X)) -> quote1(X),
                         s1(mark(X)) -> s1(X),
                       s1(active(X)) -> s1(X),
                    unquote(mark(X)) -> unquote(X),
                  unquote(active(X)) -> unquote(X),
                   unquote1(mark(X)) -> unquote1(X),
                 unquote1(active(X)) -> unquote1(X),
                 fcons(X1, mark(X2)) -> fcons(X1, X2),
               fcons(X1, active(X2)) -> fcons(X1, X2),
                 fcons(mark(X1), X2) -> fcons(X1, X2),
               fcons(active(X1), X2) -> fcons(X1, X2)
   }
  Fail