 Rankin–Selberg method

The Rankin–Selberg method represents Dirichlet series built from automorphic forms as integrals against Eisenstein series and studies them by unfolding those integrals.

The Rankin-Selberg method is a powerful technique in analytic number theory, used primarily to study L-functions attached to modular forms and automorphic forms. It is named after the mathematicians Robert Rankin and A. Selberg, who developed the theory in the mid-20th century. The method involves the construction of an "intertwining" integral that relates two L-functions.