* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            append(cons(y(),ys),x) -> cons(y(),append(ys,x))
            append(nil(),x) -> cons(x,nil())
            elem(node(l,x,r)) -> x
            if(false(),false(),n,m,xs,ys) -> listify(m,xs)
            if(false(),true(),n,m,xs,ys) -> listify(n,ys)
            if(true(),b,n,m,xs,ys) -> xs
            isEmpty(empty()) -> true()
            isEmpty(node(l,x,r)) -> false()
            left(empty()) -> empty()
            left(node(l,x,r)) -> l
            listify(n,xs) -> if(isEmpty(n)
                               ,isEmpty(left(n))
                               ,right(n)
                               ,node(left(left(n)),elem(left(n)),node(right(left(n)),elem(n),right(n)))
                               ,xs
                               ,append(xs,n))
            right(empty()) -> empty()
            right(node(l,x,r)) -> r
            toList(n) -> listify(n,nil())
        - Signature:
            {append/2,elem/1,if/6,isEmpty/1,left/1,listify/2,right/1,toList/1} / {cons/2,empty/0,false/0,nil/0,node/3
            ,true/0,y/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {append,elem,if,isEmpty,left,listify,right
            ,toList} and constructors {cons,empty,false,nil,node,true,y}
    + Applied Processor:
        Sum {left = someStrategy, right = someStrategy}
    + Details:
        ()
* Step 2: DecreasingLoops WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            append(cons(y(),ys),x) -> cons(y(),append(ys,x))
            append(nil(),x) -> cons(x,nil())
            elem(node(l,x,r)) -> x
            if(false(),false(),n,m,xs,ys) -> listify(m,xs)
            if(false(),true(),n,m,xs,ys) -> listify(n,ys)
            if(true(),b,n,m,xs,ys) -> xs
            isEmpty(empty()) -> true()
            isEmpty(node(l,x,r)) -> false()
            left(empty()) -> empty()
            left(node(l,x,r)) -> l
            listify(n,xs) -> if(isEmpty(n)
                               ,isEmpty(left(n))
                               ,right(n)
                               ,node(left(left(n)),elem(left(n)),node(right(left(n)),elem(n),right(n)))
                               ,xs
                               ,append(xs,n))
            right(empty()) -> empty()
            right(node(l,x,r)) -> r
            toList(n) -> listify(n,nil())
        - Signature:
            {append/2,elem/1,if/6,isEmpty/1,left/1,listify/2,right/1,toList/1} / {cons/2,empty/0,false/0,nil/0,node/3
            ,true/0,y/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {append,elem,if,isEmpty,left,listify,right
            ,toList} and constructors {cons,empty,false,nil,node,true,y}
    + Applied Processor:
        DecreasingLoops {bound = AnyLoop, narrow = 10}
    + Details:
        The system has following decreasing Loops:
          append(x,y){x -> cons(y(),x)} =
            append(cons(y(),x),y) ->^+ cons(y(),append(x,y))
              = C[append(x,y) = append(x,y){}]

WORST_CASE(Omega(n^1),?)