* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            U11(mark(X1),X2) -> mark(U11(X1,X2))
            U11(ok(X1),ok(X2)) -> ok(U11(X1,X2))
            active(U11(X1,X2)) -> U11(active(X1),X2)
            active(U11(tt(),L)) -> mark(s(length(L)))
            active(and(X1,X2)) -> and(active(X1),X2)
            active(and(tt(),X)) -> mark(X)
            active(cons(X1,X2)) -> cons(active(X1),X2)
            active(isNat(0())) -> mark(tt())
            active(isNat(length(V1))) -> mark(isNatList(V1))
            active(isNat(s(V1))) -> mark(isNat(V1))
            active(isNatIList(V)) -> mark(isNatList(V))
            active(isNatIList(cons(V1,V2))) -> mark(and(isNat(V1),isNatIList(V2)))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatList(cons(V1,V2))) -> mark(and(isNat(V1),isNatList(V2)))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U11(and(isNatList(L),isNat(N)),L))
            active(length(nil())) -> mark(0())
            active(s(X)) -> s(active(X))
            active(zeros()) -> mark(cons(0(),zeros()))
            and(mark(X1),X2) -> mark(and(X1,X2))
            and(ok(X1),ok(X2)) -> ok(and(X1,X2))
            cons(mark(X1),X2) -> mark(cons(X1,X2))
            cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
            isNat(ok(X)) -> ok(isNat(X))
            isNatIList(ok(X)) -> ok(isNatIList(X))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X1,X2)) -> U11(proper(X1),proper(X2))
            proper(and(X1,X2)) -> and(proper(X1),proper(X2))
            proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
            proper(isNat(X)) -> isNat(proper(X))
            proper(isNatIList(X)) -> isNatIList(proper(X))
            proper(isNatList(X)) -> isNatList(proper(X))
            proper(length(X)) -> length(proper(X))
            proper(nil()) -> ok(nil())
            proper(s(X)) -> s(proper(X))
            proper(tt()) -> ok(tt())
            proper(zeros()) -> ok(zeros())
            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:
            {U11/2,active/1,and/2,cons/2,isNat/1,isNatIList/1,isNatList/1,length/1,proper/1,s/1,top/1} / {0/0,mark/1
            ,nil/0,ok/1,tt/0,zeros/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {U11,active,and,cons,isNat,isNatIList,isNatList,length
            ,proper,s,top} and constructors {0,mark,nil,ok,tt,zeros}
    + Applied Processor:
        Sum {left = someStrategy, right = someStrategy}
    + Details:
        ()
* Step 2: DecreasingLoops WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            U11(mark(X1),X2) -> mark(U11(X1,X2))
            U11(ok(X1),ok(X2)) -> ok(U11(X1,X2))
            active(U11(X1,X2)) -> U11(active(X1),X2)
            active(U11(tt(),L)) -> mark(s(length(L)))
            active(and(X1,X2)) -> and(active(X1),X2)
            active(and(tt(),X)) -> mark(X)
            active(cons(X1,X2)) -> cons(active(X1),X2)
            active(isNat(0())) -> mark(tt())
            active(isNat(length(V1))) -> mark(isNatList(V1))
            active(isNat(s(V1))) -> mark(isNat(V1))
            active(isNatIList(V)) -> mark(isNatList(V))
            active(isNatIList(cons(V1,V2))) -> mark(and(isNat(V1),isNatIList(V2)))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatList(cons(V1,V2))) -> mark(and(isNat(V1),isNatList(V2)))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U11(and(isNatList(L),isNat(N)),L))
            active(length(nil())) -> mark(0())
            active(s(X)) -> s(active(X))
            active(zeros()) -> mark(cons(0(),zeros()))
            and(mark(X1),X2) -> mark(and(X1,X2))
            and(ok(X1),ok(X2)) -> ok(and(X1,X2))
            cons(mark(X1),X2) -> mark(cons(X1,X2))
            cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
            isNat(ok(X)) -> ok(isNat(X))
            isNatIList(ok(X)) -> ok(isNatIList(X))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X1,X2)) -> U11(proper(X1),proper(X2))
            proper(and(X1,X2)) -> and(proper(X1),proper(X2))
            proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
            proper(isNat(X)) -> isNat(proper(X))
            proper(isNatIList(X)) -> isNatIList(proper(X))
            proper(isNatList(X)) -> isNatList(proper(X))
            proper(length(X)) -> length(proper(X))
            proper(nil()) -> ok(nil())
            proper(s(X)) -> s(proper(X))
            proper(tt()) -> ok(tt())
            proper(zeros()) -> ok(zeros())
            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:
            {U11/2,active/1,and/2,cons/2,isNat/1,isNatIList/1,isNatList/1,length/1,proper/1,s/1,top/1} / {0/0,mark/1
            ,nil/0,ok/1,tt/0,zeros/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {U11,active,and,cons,isNat,isNatIList,isNatList,length
            ,proper,s,top} and constructors {0,mark,nil,ok,tt,zeros}
    + Applied Processor:
        DecreasingLoops {bound = AnyLoop, narrow = 10}
    + Details:
        The system has following decreasing Loops:
          U11(x,y){x -> mark(x)} =
            U11(mark(x),y) ->^+ mark(U11(x,y))
              = C[U11(x,y) = U11(x,y){}]

WORST_CASE(Omega(n^1),?)