Heinrich Brandt

Heinrich Brandt (8 November 1886, in Feudingen – 9 October 1954, in Halle, Saxony-Anhalt) was a German mathematician who was the first to develop the concept of a groupoid.

In 1912 he attained his doctorate; he was a student of Heinrich Martin Weber.

A Brandt matrix is a computational way of describing the Hecke operator action on theta series as modular forms.

The theory was developed in part by Brandt's student Martin Eichler.

It offers an algorithmic approach for machine computation (in that theta series span spaces of modular forms); the theory is now considered by means of Brandt modules.