The formal series symmetry approach of obtaining symmetries of a highe
r-dimensional partial differential equation is treated as an alternati
ve way. For a breaking soliton equation which possesses a (1 + 1)-dime
nsional-like recursion operator, six sets of generalized symmetries ar
e explicitly given. It is known that the truncated formal series symme
tries of the KP and Toda equations constitute the generalized W-infini
ty algebra. From this paper we find that the generalized W-infinity al
gebra can also be realized by means of the nontruncated formal series
symmetries.