Integral Recurrences from A to Z

TL;DR

This paper introduces the Almkvist--Zeilberger (AZ) method of definite integration through case studies, highlighting its significance and providing an integral-based proof of the irrationality of e.

Contribution

It presents the AZ method with illustrative case studies and emphasizes its importance, including a novel integral proof of e's irrationality.

Findings

AZ method effectively solves definite integrals

Case studies demonstrate the method's versatility

Provides a new proof of e's irrationality

Abstract

George Boros and Victor Moll's masterpiece "Irresistible Integrals" does well to include a suitably-titled appendix, "The Revolutionary WZ Method," which gives a brief overview of the celebrated Wilf--Zeilberger method of definite summation. Paradoxically, "Irresistible Integrals" does not contain the suitably-titled appendix, "The Revolutionary AZ Method," which would have been an excellent place to give a brief overview of the Almkvist--Zeilberger method of definite integration! This omission can be forgiven, but once realized it must be rectified. The remarkable AZ machinery deserves to be more widely known to the general public than it is. We will do our part by presenting a series of case studies that culminate in a -- fun but overkill -- integral-based proof that $e$ is irrational.