MAYBE
MAYBE
TRS:
 {
                  mark(__(X1, X2)) -> active(__(mark(X1), mark(X2))),
                       mark(nil()) -> active(nil()),
                        mark(tt()) -> active(tt()),
                      mark(U11(X)) -> active(U11(mark(X))),
                      mark(U22(X)) -> active(U22(mark(X))),
                   mark(isList(X)) -> active(isList(X)),
                 mark(U21(X1, X2)) -> active(U21(mark(X1), X2)),
                      mark(U31(X)) -> active(U31(mark(X))),
                      mark(U42(X)) -> active(U42(mark(X))),
                 mark(isNeList(X)) -> active(isNeList(X)),
                 mark(U41(X1, X2)) -> active(U41(mark(X1), X2)),
                      mark(U52(X)) -> active(U52(mark(X))),
                 mark(U51(X1, X2)) -> active(U51(mark(X1), X2)),
                      mark(U61(X)) -> active(U61(mark(X))),
                      mark(U72(X)) -> active(U72(mark(X))),
                    mark(isPal(X)) -> active(isPal(X)),
                 mark(U71(X1, X2)) -> active(U71(mark(X1), X2)),
                      mark(U81(X)) -> active(U81(mark(X))),
                    mark(isQid(X)) -> active(isQid(X)),
                  mark(isNePal(X)) -> active(isNePal(X)),
                         mark(a()) -> active(a()),
                         mark(e()) -> active(e()),
                         mark(i()) -> active(i()),
                         mark(o()) -> active(o()),
                         mark(u()) -> active(u()),
                  __(X1, mark(X2)) -> __(X1, X2),
                __(X1, active(X2)) -> __(X1, X2),
                  __(mark(X1), X2) -> __(X1, X2),
                __(active(X1), X2) -> __(X1, X2),
              active(__(X, nil())) -> mark(X),
           active(__(__(X, Y), Z)) -> mark(__(X, __(Y, Z))),
              active(__(nil(), X)) -> mark(X),
                 active(U11(tt())) -> mark(tt()),
                 active(U22(tt())) -> mark(tt()),
                 active(isList(V)) -> mark(U11(isNeList(V))),
        active(isList(__(V1, V2))) -> mark(U21(isList(V1), V2)),
             active(isList(nil())) -> mark(tt()),
             active(U21(tt(), V2)) -> mark(U22(isList(V2))),
                 active(U31(tt())) -> mark(tt()),
                 active(U42(tt())) -> mark(tt()),
               active(isNeList(V)) -> mark(U31(isQid(V))),
      active(isNeList(__(V1, V2))) -> mark(U41(isList(V1), V2)),
      active(isNeList(__(V1, V2))) -> mark(U51(isNeList(V1), V2)),
             active(U41(tt(), V2)) -> mark(U42(isNeList(V2))),
                 active(U52(tt())) -> mark(tt()),
             active(U51(tt(), V2)) -> mark(U52(isList(V2))),
                 active(U61(tt())) -> mark(tt()),
                 active(U72(tt())) -> mark(tt()),
                  active(isPal(V)) -> mark(U81(isNePal(V))),
              active(isPal(nil())) -> mark(tt()),
              active(U71(tt(), P)) -> mark(U72(isPal(P))),
                 active(U81(tt())) -> mark(tt()),
                active(isQid(a())) -> mark(tt()),
                active(isQid(e())) -> mark(tt()),
                active(isQid(i())) -> mark(tt()),
                active(isQid(o())) -> mark(tt()),
                active(isQid(u())) -> mark(tt()),
                active(isNePal(V)) -> mark(U61(isQid(V))),
  active(isNePal(__(I, __(P, I)))) -> mark(U71(isQid(I), P)),
                      U11(mark(X)) -> U11(X),
                    U11(active(X)) -> U11(X),
                      U22(mark(X)) -> U22(X),
                    U22(active(X)) -> U22(X),
                   isList(mark(X)) -> isList(X),
                 isList(active(X)) -> isList(X),
                 U21(X1, mark(X2)) -> U21(X1, X2),
               U21(X1, active(X2)) -> U21(X1, X2),
                 U21(mark(X1), X2) -> U21(X1, X2),
               U21(active(X1), X2) -> U21(X1, X2),
                      U31(mark(X)) -> U31(X),
                    U31(active(X)) -> U31(X),
                      U42(mark(X)) -> U42(X),
                    U42(active(X)) -> U42(X),
                 isNeList(mark(X)) -> isNeList(X),
               isNeList(active(X)) -> isNeList(X),
                 U41(X1, mark(X2)) -> U41(X1, X2),
               U41(X1, active(X2)) -> U41(X1, X2),
                 U41(mark(X1), X2) -> U41(X1, X2),
               U41(active(X1), X2) -> U41(X1, X2),
                      U52(mark(X)) -> U52(X),
                    U52(active(X)) -> U52(X),
                 U51(X1, mark(X2)) -> U51(X1, X2),
               U51(X1, active(X2)) -> U51(X1, X2),
                 U51(mark(X1), X2) -> U51(X1, X2),
               U51(active(X1), X2) -> U51(X1, X2),
                      U61(mark(X)) -> U61(X),
                    U61(active(X)) -> U61(X),
                      U72(mark(X)) -> U72(X),
                    U72(active(X)) -> U72(X),
                    isPal(mark(X)) -> isPal(X),
                  isPal(active(X)) -> isPal(X),
                 U71(X1, mark(X2)) -> U71(X1, X2),
               U71(X1, active(X2)) -> U71(X1, X2),
                 U71(mark(X1), X2) -> U71(X1, X2),
               U71(active(X1), X2) -> U71(X1, X2),
                      U81(mark(X)) -> U81(X),
                    U81(active(X)) -> U81(X),
                    isQid(mark(X)) -> isQid(X),
                  isQid(active(X)) -> isQid(X),
                  isNePal(mark(X)) -> isNePal(X),
                isNePal(active(X)) -> isNePal(X)
 }
 DUP: We consider a non-duplicating system.
  Trs:
   {
                    mark(__(X1, X2)) -> active(__(mark(X1), mark(X2))),
                         mark(nil()) -> active(nil()),
                          mark(tt()) -> active(tt()),
                        mark(U11(X)) -> active(U11(mark(X))),
                        mark(U22(X)) -> active(U22(mark(X))),
                     mark(isList(X)) -> active(isList(X)),
                   mark(U21(X1, X2)) -> active(U21(mark(X1), X2)),
                        mark(U31(X)) -> active(U31(mark(X))),
                        mark(U42(X)) -> active(U42(mark(X))),
                   mark(isNeList(X)) -> active(isNeList(X)),
                   mark(U41(X1, X2)) -> active(U41(mark(X1), X2)),
                        mark(U52(X)) -> active(U52(mark(X))),
                   mark(U51(X1, X2)) -> active(U51(mark(X1), X2)),
                        mark(U61(X)) -> active(U61(mark(X))),
                        mark(U72(X)) -> active(U72(mark(X))),
                      mark(isPal(X)) -> active(isPal(X)),
                   mark(U71(X1, X2)) -> active(U71(mark(X1), X2)),
                        mark(U81(X)) -> active(U81(mark(X))),
                      mark(isQid(X)) -> active(isQid(X)),
                    mark(isNePal(X)) -> active(isNePal(X)),
                           mark(a()) -> active(a()),
                           mark(e()) -> active(e()),
                           mark(i()) -> active(i()),
                           mark(o()) -> active(o()),
                           mark(u()) -> active(u()),
                    __(X1, mark(X2)) -> __(X1, X2),
                  __(X1, active(X2)) -> __(X1, X2),
                    __(mark(X1), X2) -> __(X1, X2),
                  __(active(X1), X2) -> __(X1, X2),
                active(__(X, nil())) -> mark(X),
             active(__(__(X, Y), Z)) -> mark(__(X, __(Y, Z))),
                active(__(nil(), X)) -> mark(X),
                   active(U11(tt())) -> mark(tt()),
                   active(U22(tt())) -> mark(tt()),
                   active(isList(V)) -> mark(U11(isNeList(V))),
          active(isList(__(V1, V2))) -> mark(U21(isList(V1), V2)),
               active(isList(nil())) -> mark(tt()),
               active(U21(tt(), V2)) -> mark(U22(isList(V2))),
                   active(U31(tt())) -> mark(tt()),
                   active(U42(tt())) -> mark(tt()),
                 active(isNeList(V)) -> mark(U31(isQid(V))),
        active(isNeList(__(V1, V2))) -> mark(U41(isList(V1), V2)),
        active(isNeList(__(V1, V2))) -> mark(U51(isNeList(V1), V2)),
               active(U41(tt(), V2)) -> mark(U42(isNeList(V2))),
                   active(U52(tt())) -> mark(tt()),
               active(U51(tt(), V2)) -> mark(U52(isList(V2))),
                   active(U61(tt())) -> mark(tt()),
                   active(U72(tt())) -> mark(tt()),
                    active(isPal(V)) -> mark(U81(isNePal(V))),
                active(isPal(nil())) -> mark(tt()),
                active(U71(tt(), P)) -> mark(U72(isPal(P))),
                   active(U81(tt())) -> mark(tt()),
                  active(isQid(a())) -> mark(tt()),
                  active(isQid(e())) -> mark(tt()),
                  active(isQid(i())) -> mark(tt()),
                  active(isQid(o())) -> mark(tt()),
                  active(isQid(u())) -> mark(tt()),
                  active(isNePal(V)) -> mark(U61(isQid(V))),
    active(isNePal(__(I, __(P, I)))) -> mark(U71(isQid(I), P)),
                        U11(mark(X)) -> U11(X),
                      U11(active(X)) -> U11(X),
                        U22(mark(X)) -> U22(X),
                      U22(active(X)) -> U22(X),
                     isList(mark(X)) -> isList(X),
                   isList(active(X)) -> isList(X),
                   U21(X1, mark(X2)) -> U21(X1, X2),
                 U21(X1, active(X2)) -> U21(X1, X2),
                   U21(mark(X1), X2) -> U21(X1, X2),
                 U21(active(X1), X2) -> U21(X1, X2),
                        U31(mark(X)) -> U31(X),
                      U31(active(X)) -> U31(X),
                        U42(mark(X)) -> U42(X),
                      U42(active(X)) -> U42(X),
                   isNeList(mark(X)) -> isNeList(X),
                 isNeList(active(X)) -> isNeList(X),
                   U41(X1, mark(X2)) -> U41(X1, X2),
                 U41(X1, active(X2)) -> U41(X1, X2),
                   U41(mark(X1), X2) -> U41(X1, X2),
                 U41(active(X1), X2) -> U41(X1, X2),
                        U52(mark(X)) -> U52(X),
                      U52(active(X)) -> U52(X),
                   U51(X1, mark(X2)) -> U51(X1, X2),
                 U51(X1, active(X2)) -> U51(X1, X2),
                   U51(mark(X1), X2) -> U51(X1, X2),
                 U51(active(X1), X2) -> U51(X1, X2),
                        U61(mark(X)) -> U61(X),
                      U61(active(X)) -> U61(X),
                        U72(mark(X)) -> U72(X),
                      U72(active(X)) -> U72(X),
                      isPal(mark(X)) -> isPal(X),
                    isPal(active(X)) -> isPal(X),
                   U71(X1, mark(X2)) -> U71(X1, X2),
                 U71(X1, active(X2)) -> U71(X1, X2),
                   U71(mark(X1), X2) -> U71(X1, X2),
                 U71(active(X1), X2) -> U71(X1, X2),
                        U81(mark(X)) -> U81(X),
                      U81(active(X)) -> U81(X),
                      isQid(mark(X)) -> isQid(X),
                    isQid(active(X)) -> isQid(X),
                    isNePal(mark(X)) -> isNePal(X),
                  isNePal(active(X)) -> isNePal(X)
   }
  Fail