This database collects special values of modular functions at CM points, with particular emphasis on the Dedekind eta function \( \eta(\tau) \) and the modular \( j \)-invariant.
The Dedekind eta function is defined by \[ \eta(\tau) = q^{1/24} \prod_{n=1}^{\infty} (1 - q^n), \quad q = e^{2\pi i\tau}, \] and transforms as a modular form of weight \( \tfrac{1}{2} \).
The modular invariant \( j(\tau) \) classifies elliptic curves over \( \mathbb{C} \) up to isomorphism. For CM points \( \tau \), the value \( j(\tau) \) is an algebraic integer generating the Hilbert class field of the corresponding imaginary quadratic order.