YES(?,POLY)

'Pop* (timeout of 60.0 seconds)'
--------------------------------
Answer:           YES(?,POLY)
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  app(nil(), xs) -> nil()
     , app(cons(x, xs), ys) -> cons(x, app(xs, ys))}

Proof Output:    
  The input was oriented with the instance of POP* as induced by the precedence
  
   empty
  
  and safe mapping
  
   safe(app) = {2}, safe(nil) = {}, safe(cons) = {1, 2} .
  
  For your convenience, here is the input in predicative notation:
  
   Rules:
    {  app(nil(); xs) -> nil()
     , app(cons(; x, xs); ys) -> cons(; x, app(xs; ys))}