(VAR x y z)
(RULES
+(*(x,y),*(x,z)) -> *(x,+(y,z))
+(+(x,y),z) -> +(x,+(y,z))
+(*(x,y),+(*(x,z),u)) -> +(*(x,+(y,z)),u)
)
(COMMENT Example 4 in \cite{DKM90})