MAYBE

We are left with following problem, upon which TcT provides the
certificate MAYBE.

Strict Trs:
  { a____(X1, X2) -> __(X1, X2)
  , a____(X, nil()) -> mark(X)
  , a____(__(X, Y), Z) -> a____(mark(X), a____(mark(Y), mark(Z)))
  , a____(nil(), X) -> mark(X)
  , mark(__(X1, X2)) -> a____(mark(X1), mark(X2))
  , mark(nil()) -> nil()
  , mark(tt()) -> tt()
  , mark(a()) -> a()
  , mark(e()) -> e()
  , mark(i()) -> i()
  , mark(o()) -> o()
  , mark(u()) -> u()
  , mark(U11(X)) -> a__U11(mark(X))
  , mark(U21(X1, X2)) -> a__U21(mark(X1), X2)
  , mark(U22(X)) -> a__U22(mark(X))
  , mark(isList(X)) -> a__isList(X)
  , mark(U31(X)) -> a__U31(mark(X))
  , mark(U41(X1, X2)) -> a__U41(mark(X1), X2)
  , mark(U42(X)) -> a__U42(mark(X))
  , mark(isNeList(X)) -> a__isNeList(X)
  , mark(U51(X1, X2)) -> a__U51(mark(X1), X2)
  , mark(U52(X)) -> a__U52(mark(X))
  , mark(U61(X)) -> a__U61(mark(X))
  , mark(U71(X1, X2)) -> a__U71(mark(X1), X2)
  , mark(U72(X)) -> a__U72(mark(X))
  , mark(isPal(X)) -> a__isPal(X)
  , mark(U81(X)) -> a__U81(mark(X))
  , mark(isQid(X)) -> a__isQid(X)
  , mark(isNePal(X)) -> a__isNePal(X)
  , a__U11(X) -> U11(X)
  , a__U11(tt()) -> tt()
  , a__U21(X1, X2) -> U21(X1, X2)
  , a__U21(tt(), V2) -> a__U22(a__isList(V2))
  , a__U22(X) -> U22(X)
  , a__U22(tt()) -> tt()
  , a__isList(V) -> a__U11(a__isNeList(V))
  , a__isList(X) -> isList(X)
  , a__isList(__(V1, V2)) -> a__U21(a__isList(V1), V2)
  , a__isList(nil()) -> tt()
  , a__U31(X) -> U31(X)
  , a__U31(tt()) -> tt()
  , a__U41(X1, X2) -> U41(X1, X2)
  , a__U41(tt(), V2) -> a__U42(a__isNeList(V2))
  , a__U42(X) -> U42(X)
  , a__U42(tt()) -> tt()
  , a__isNeList(V) -> a__U31(a__isQid(V))
  , a__isNeList(X) -> isNeList(X)
  , a__isNeList(__(V1, V2)) -> a__U41(a__isList(V1), V2)
  , a__isNeList(__(V1, V2)) -> a__U51(a__isNeList(V1), V2)
  , a__U51(X1, X2) -> U51(X1, X2)
  , a__U51(tt(), V2) -> a__U52(a__isList(V2))
  , a__U52(X) -> U52(X)
  , a__U52(tt()) -> tt()
  , a__U61(X) -> U61(X)
  , a__U61(tt()) -> tt()
  , a__U71(X1, X2) -> U71(X1, X2)
  , a__U71(tt(), P) -> a__U72(a__isPal(P))
  , a__U72(X) -> U72(X)
  , a__U72(tt()) -> tt()
  , a__isPal(V) -> a__U81(a__isNePal(V))
  , a__isPal(X) -> isPal(X)
  , a__isPal(nil()) -> tt()
  , a__U81(X) -> U81(X)
  , a__U81(tt()) -> tt()
  , a__isQid(X) -> isQid(X)
  , a__isQid(a()) -> tt()
  , a__isQid(e()) -> tt()
  , a__isQid(i()) -> tt()
  , a__isQid(o()) -> tt()
  , a__isQid(u()) -> tt()
  , a__isNePal(V) -> a__U61(a__isQid(V))
  , a__isNePal(X) -> isNePal(X)
  , a__isNePal(__(I, __(P, I))) -> a__U71(a__isQid(I), P) }
Obligation:
  innermost runtime complexity
Answer:
  MAYBE

The input cannot be shown compatible

Arrrr..