Erich Hecke
The life of Erich Hecke - Bridge between Primes and Calculus
Hecke Operator
Operators acting on modular forms.
\[ T_n f(z) = \sum_{d=1}^{\infty} c(n, d, f) q^{d} \]
Sources: https://mathshistory.st-andrews.ac.uk/Biographies/Hecke/
