YES(?,POLY)

'Pop* (timeout of 60.0 seconds)'
--------------------------------
Answer:           YES(?,POLY)
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  merge(x, nil()) -> x
     , merge(nil(), y) -> y
     , merge(++(x, y), ++(u(), v())) -> ++(x, merge(y, ++(u(), v())))
     , merge(++(x, y), ++(u(), v())) -> ++(u(), merge(++(x, y), v()))}

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