* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            a__first(X1,X2) -> first(X1,X2)
            a__first(0(),Z) -> nil()
            a__first(s(X),cons(Y,Z)) -> cons(mark(Y),first(X,Z))
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            a__sel(X1,X2) -> sel(X1,X2)
            a__sel(0(),cons(X,Z)) -> mark(X)
            a__sel(s(X),cons(Y,Z)) -> a__sel(mark(X),mark(Z))
            mark(0()) -> 0()
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(first(X1,X2)) -> a__first(mark(X1),mark(X2))
            mark(from(X)) -> a__from(mark(X))
            mark(nil()) -> nil()
            mark(s(X)) -> s(mark(X))
            mark(sel(X1,X2)) -> a__sel(mark(X1),mark(X2))
        - Signature:
            {a__first/2,a__from/1,a__sel/2,mark/1} / {0/0,cons/2,first/2,from/1,nil/0,s/1,sel/2}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__first,a__from,a__sel,mark} and constructors {0,cons
            ,first,from,nil,s,sel}
    + Applied Processor:
        Sum {left = someStrategy, right = someStrategy}
    + Details:
        ()
* Step 2: DecreasingLoops WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            a__first(X1,X2) -> first(X1,X2)
            a__first(0(),Z) -> nil()
            a__first(s(X),cons(Y,Z)) -> cons(mark(Y),first(X,Z))
            a__from(X) -> cons(mark(X),from(s(X)))
            a__from(X) -> from(X)
            a__sel(X1,X2) -> sel(X1,X2)
            a__sel(0(),cons(X,Z)) -> mark(X)
            a__sel(s(X),cons(Y,Z)) -> a__sel(mark(X),mark(Z))
            mark(0()) -> 0()
            mark(cons(X1,X2)) -> cons(mark(X1),X2)
            mark(first(X1,X2)) -> a__first(mark(X1),mark(X2))
            mark(from(X)) -> a__from(mark(X))
            mark(nil()) -> nil()
            mark(s(X)) -> s(mark(X))
            mark(sel(X1,X2)) -> a__sel(mark(X1),mark(X2))
        - Signature:
            {a__first/2,a__from/1,a__sel/2,mark/1} / {0/0,cons/2,first/2,from/1,nil/0,s/1,sel/2}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {a__first,a__from,a__sel,mark} and constructors {0,cons
            ,first,from,nil,s,sel}
    + Applied Processor:
        DecreasingLoops {bound = AnyLoop, narrow = 10}
    + Details:
        The system has following decreasing Loops:
          mark(x){x -> cons(x,y)} =
            mark(cons(x,y)) ->^+ cons(mark(x),y)
              = C[mark(x) = mark(x){}]

WORST_CASE(Omega(n^1),?)