(VAR x y xs fun)
(RULES
  app(app(plus, x), 0) -> x
  app(app(plus, x), app(s, y)) -> app(s, app(app(plus, x), y))
  app(app(app(f, 0), app(s, 0)), x) -> app(app(app(f, x), app(app(plus, x), x)), x)
  app(app(g, x), y) -> x
  app(app(g, x), y) -> y

  app(app(map,fun),nil) -> nil
  app(app(map,fun),app(app(cons,x),xs)) -> app(app(cons,app(fun,x)),app(app(map,fun),xs))

  app(app(filter,fun),nil) -> nil
  app(app(filter,fun),app(app(cons,x),xs)) -> app(app(app(app(filter2,app(fun, x)),fun),x),xs)
  app(app(app(app(filter2,true),fun),x),xs) -> app(app(cons,x),app(app(filter,fun),xs))
  app(app(app(app(filter2,false),fun),x),xs) -> app(app(filter,fun),xs)

)
(STRATEGY INNERMOST)