Welcome to Week 2 of "Analytic Combinatorics." This week, we address the idea of using multivariate generating functions to study combinatorial parameters, such as leaves in trees or cycles in permutations. ---------- Lecture 3: Combinatorial Parameters and MGFs. This lecture describes the process of adding variables to mark parameters and then using the constructions form Lectures 1 and 2 and natural extensions of the transfer theorems to define multivariate GFs that contain information about parameters. We concentrate on bivariate generating functions (BGFs), where one variable marks the size of an object and the other marks the value of a parameter. After studying ways of computing the mean, standard deviation and other moments from BGFs, we consider several examples in some detail. ---------- Your assignment for this week, due at 11:59PM on Thursday, March 31, 2022 is to write up and submit solutions to Note III.17 and Web Exercise III.3 on the "Analytic Combinatorics" booksite. Please note that "Notes" in the book are often written as statements instead of questions, so the versions on the booksite are slightly reworded to clarify what you need to do. As usual, submit a potential exam question on the week's material. Submit files named "AC2-Q1.pdf" "AC2-Q2.pdf" "AC2-QQ.pdf" via codePost. RS