MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          U11(mark(X1),X2,X3) -> mark(U11(X1,X2,X3))
          U11(ok(X1),ok(X2),ok(X3)) -> ok(U11(X1,X2,X3))
          U12(mark(X1),X2) -> mark(U12(X1,X2))
          U12(ok(X1),ok(X2)) -> ok(U12(X1,X2))
          U13(mark(X)) -> mark(U13(X))
          U13(ok(X)) -> ok(U13(X))
          U21(mark(X1),X2) -> mark(U21(X1,X2))
          U21(ok(X1),ok(X2)) -> ok(U21(X1,X2))
          U22(mark(X)) -> mark(U22(X))
          U22(ok(X)) -> ok(U22(X))
          U31(mark(X1),X2) -> mark(U31(X1,X2))
          U31(ok(X1),ok(X2)) -> ok(U31(X1,X2))
          U41(mark(X1),X2,X3) -> mark(U41(X1,X2,X3))
          U41(ok(X1),ok(X2),ok(X3)) -> ok(U41(X1,X2,X3))
          active(U11(X1,X2,X3)) -> U11(active(X1),X2,X3)
          active(U11(tt(),V1,V2)) -> mark(U12(isNat(V1),V2))
          active(U12(X1,X2)) -> U12(active(X1),X2)
          active(U12(tt(),V2)) -> mark(U13(isNat(V2)))
          active(U13(X)) -> U13(active(X))
          active(U13(tt())) -> mark(tt())
          active(U21(X1,X2)) -> U21(active(X1),X2)
          active(U21(tt(),V1)) -> mark(U22(isNat(V1)))
          active(U22(X)) -> U22(active(X))
          active(U22(tt())) -> mark(tt())
          active(U31(X1,X2)) -> U31(active(X1),X2)
          active(U31(tt(),N)) -> mark(N)
          active(U41(X1,X2,X3)) -> U41(active(X1),X2,X3)
          active(U41(tt(),M,N)) -> mark(s(plus(N,M)))
          active(and(X1,X2)) -> and(active(X1),X2)
          active(and(tt(),X)) -> mark(X)
          active(isNat(0())) -> mark(tt())
          active(isNat(plus(V1,V2))) -> mark(U11(and(isNatKind(V1),isNatKind(V2)),V1,V2))
          active(isNat(s(V1))) -> mark(U21(isNatKind(V1),V1))
          active(isNatKind(0())) -> mark(tt())
          active(isNatKind(plus(V1,V2))) -> mark(and(isNatKind(V1),isNatKind(V2)))
          active(isNatKind(s(V1))) -> mark(isNatKind(V1))
          active(plus(N,0())) -> mark(U31(and(isNat(N),isNatKind(N)),N))
          active(plus(N,s(M))) -> mark(U41(and(and(isNat(M),isNatKind(M)),and(isNat(N),isNatKind(N))),M,N))
          active(plus(X1,X2)) -> plus(X1,active(X2))
          active(plus(X1,X2)) -> plus(active(X1),X2)
          active(s(X)) -> s(active(X))
          and(mark(X1),X2) -> mark(and(X1,X2))
          and(ok(X1),ok(X2)) -> ok(and(X1,X2))
          isNat(ok(X)) -> ok(isNat(X))
          isNatKind(ok(X)) -> ok(isNatKind(X))
          plus(X1,mark(X2)) -> mark(plus(X1,X2))
          plus(mark(X1),X2) -> mark(plus(X1,X2))
          plus(ok(X1),ok(X2)) -> ok(plus(X1,X2))
          proper(0()) -> ok(0())
          proper(U11(X1,X2,X3)) -> U11(proper(X1),proper(X2),proper(X3))
          proper(U12(X1,X2)) -> U12(proper(X1),proper(X2))
          proper(U13(X)) -> U13(proper(X))
          proper(U21(X1,X2)) -> U21(proper(X1),proper(X2))
          proper(U22(X)) -> U22(proper(X))
          proper(U31(X1,X2)) -> U31(proper(X1),proper(X2))
          proper(U41(X1,X2,X3)) -> U41(proper(X1),proper(X2),proper(X3))
          proper(and(X1,X2)) -> and(proper(X1),proper(X2))
          proper(isNat(X)) -> isNat(proper(X))
          proper(isNatKind(X)) -> isNatKind(proper(X))
          proper(plus(X1,X2)) -> plus(proper(X1),proper(X2))
          proper(s(X)) -> s(proper(X))
          proper(tt()) -> ok(tt())
          s(mark(X)) -> mark(s(X))
          s(ok(X)) -> ok(s(X))
          top(mark(X)) -> top(proper(X))
          top(ok(X)) -> top(active(X))
      - Signature:
          {U11/3,U12/2,U13/1,U21/2,U22/1,U31/2,U41/3,active/1,and/2,isNat/1,isNatKind/1,plus/2,proper/1,s/1
          ,top/1} / {0/0,mark/1,ok/1,tt/0}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {U11,U12,U13,U21,U22,U31,U41,active,and,isNat,isNatKind
          ,plus,proper,s,top} and constructors {0,mark,ok,tt}
  + Applied Processor:
      NaturalMI {miDimension = 3, miDegree = 3, miKind = Algebraic, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE