NO

1 decompositions
 #1 -----------
   1: b() -> c()
   2: b() -> f(c())

unjoinable peak
    c()
*<- b() ->*
    f(c())
NOTE: input TRS is reduced

original is
   1: b() -> c()
   2: b() -> f(c())
   3: c() -> c()

reduced to
   1: b() -> c()
   2: b() -> f(c())