NO

1 decompositions
 #1 -----------
   1: +(0(),0()) -> 0()
   2: +(s(0()),x1) -> s(+(0(),x1))
   3: +(x2,s(x3)) -> s(+(x3,x2))
   4: s(s(x4)) -> x4

unjoinable peak
    +(x11,0())
*<- +(s(0()),s(x11)) ->*
    +(0(),x11)