Sketch of a Program for Universal Automorphic Functions to Capture Monstrous Moonshine

Igor Frenkel, Robert Penner

We review and reformulate old and prove new results about the triad ${\mathrm{PPSL}}_2(\mathbb{Z})\subseteq {\mathrm{PPSL}}_2(\mathbb{R})\circlearrowright pps{l}_2(\mathbb{R})$, which prov…