MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          active(cons(X1,X2)) -> cons(active(X1),X2)
          active(from(X)) -> from(active(X))
          active(from(X)) -> mark(cons(X,from(s(X))))
          active(length(cons(X,Y))) -> mark(s(length1(Y)))
          active(length(nil())) -> mark(0())
          active(length1(X)) -> mark(length(X))
          active(s(X)) -> s(active(X))
          cons(mark(X1),X2) -> mark(cons(X1,X2))
          cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
          from(mark(X)) -> mark(from(X))
          from(ok(X)) -> ok(from(X))
          length(ok(X)) -> ok(length(X))
          length1(ok(X)) -> ok(length1(X))
          proper(0()) -> ok(0())
          proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
          proper(from(X)) -> from(proper(X))
          proper(length(X)) -> length(proper(X))
          proper(length1(X)) -> length1(proper(X))
          proper(nil()) -> ok(nil())
          proper(s(X)) -> s(proper(X))
          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:
          {active/1,cons/2,from/1,length/1,length1/1,proper/1,s/1,top/1} / {0/0,mark/1,nil/0,ok/1}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {active,cons,from,length,length1,proper,s
          ,top} and constructors {0,mark,nil,ok}
  + Applied Processor:
      EmptyProcessor
  + Details:
      The problem is still open.
MAYBE