(VAR x y z)
(RULES
  -(+(x,y)) -> +(-(x),-(y))
  +(x,y) -> +(y,x)
  +(+(x,y),z) -> +(x,+(y,z))
)
(COMMENT
full experiments for [35]
submitted by: Takahito Aoto and Yoshihito Toyama
)