The odd-order radial limit of Ramanujan's third-order mock theta function
Abstract
We prove that for every odd integer k ≥ 3 and every primitive kth root of unity ζ_k, lim_{r→1⁻} f(rζ_k) = (4/3)·T_k, where T_k is a finite cyclotomic sum in ℤ[ζ_k]. This is the odd-order companion to the Folsom–Ono–Rhoades even-order radial limit formula. The factor 4/3 arises from the k-periodicity of the q-Pochhammer symbol on the unit circle: each complete cycle contributes a factor of 2, squaring in the denominator yields 4, and the resulting geometric series collapses to 4/3. "v4: Corrects v3, which was uploaded in error. This version restores the original odd-order radial limit theorem."
Fields of Study & Subjects
Advanced Mathematical Identities
Advanced Combinatorial Mathematics
Mathematical functions and polynomials
Publication details
- Journal / source
- Zenodo (CERN European Organization for Nuclear Research)
- Publication date
- 15 May 2026
- Language
- EN
- Document type
- Preprint