(VAR y x)
(RULES
   +(0,y) -> y
   +(s(x),y) -> s(+(x,y))
   +(x,0) -> +(0,x)
   +(x,s(y)) -> +(s(y),x)
)
(COMMENT
doi:10.4230/LIPIcs.FSCD.2016.33
[36] Example 23
submitted by: Takahito Aoto
)