An object of the class FormalSeries is a list \{P,n\} where P is an element of a polynomial ring and n is an integer representing the precision (the terms in degree strictly greater than n are considered zero).
The object FormalSeries is a type, with ancestor classes BasicList < Thing.
The source of this document is in /build/reproducible-path/macaulay2-1.25.05+ds/M2/Macaulay2/packages/FormalGroupLaws.m2:342:0.