Bilateral Bailey Lattices and Andrews–Gordon Type Identities

We show that the Bailey lattice can be extended to a bilateral version in just a few lines from the bilateral Bailey lemma, using a very simple lemma transforming bilateral Bailey pairs relative to $a$ into bilateral Bailey pairs relative to $a/q$. Using this and similar lemmas, we give bilateral versions and simple proofs of other (new and known) Bailey lattices, including a Bailey lattice of Warnaar and the inverses of Bailey lattices of Lovejoy. As consequences of our bilateral point of view, we derive new $m$-versions of the Andrews–Gordon identities, Bressoud's identities, a new companion to Bressoud's identities, and the Bressoud–Göllnitz–Gordon identities. Finally, we give a new elementary proof of another very general identity of Bressoud using one of our Bailey lattices.