Berezin integral
In mathematical physics, the Berezin integral, named after Felix Berezin (also known as Grassmann integral, after Hermann Grassmann) is a way to define integration for functions of Grassmann variables (elements of the exterior algebra). It is not an integral in the Lebesgue sense; the word "integral" is used because the Berezin integral has properties analogous to the Lebesgue integral and because it extends the path integral in physics, where it is used as a sum over histories for fermions.