NO

1 decompositions
 #0 -----------
   1: +(0(),y) -> y
   2: +(s(0()),y) -> s(y)
   3: +(s(s(x)),y) -> s(s(+(y,x)))
   4: +(x,+(y,z)) -> +(+(z,y),x)

unjoinable peak
    +(_y13,_y14)
*<- +(0(),+(_y13,_y14)) ->*
    +(+(_y14,_y13),0())