  Beginning with the chapter Properties of Elective Functions, Boole  developed general theorems for working with elective functions and equations  in his algebra of logic—the Expansion (or Development)  Theorem (described above in Section 3.5) and the properties of constituents  are discussed in this chapter.  He used the power series expansion of an elective function in his proof of the  one-variable  case of the Expansion Theorem (MAL, p. 60), perhaps intending to apply it  to rational elective functions. 