FINDING: E8 lattice theta series is a modular form of weight 4; K3 surface periods and curve counts are governed by modular forms; L-functions of elliptic curves are modular. MATH: - E8 lattice theta series: \ (₄₈ () = ₕ ₄₈ q^|v|²/2 = 1 + 240 ₍=₁^ ₃ (n) qⁿ\), where \ (q = e^2 i \), \ (₃ (n) = ₃|₍ d³\). This is a modular form of weight 4 for \ (SL₂ (Z) \). - K3 surface periods: The period domain is a type IV symmetric domain; the transcendental lattice has rank 22-ρ (ρ = Picard number). Curve counts on K3 surfaces yield generating functions that are modular forms (e. g. , quasimodular forms for genus 0 Gromov-Witten invariants). - L-function of an elliptic curve: \ (L (E, s) = ₍=₁^ aₙ n^-s\), with \ (aₚ = p - \#E (Fₚ) \). Modularity: \ (L (E, s) \) equals the L-function of a weight 2 newform \ (f () = aₙ qⁿ\). CONNECTION: - E8 lattice is the root system of the exceptional Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence. com
Andrew Stewart Caldin (Wed,) studied this question.