Formal Calculus
James Lepowsky, Haisheng Li · Birkhäuser Boston eBooks · 2004
In this chapter we shall present the elementary formal calculus that is basic in vertex operator algebra theory. Formal calculus has been treated in Chapters 2 and, 8 of [FLM6] and, in [FHL]. For our present purposes and, to make this work self-contained, we present here a full but slightly different treatment.