In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

was originally used to describe a wave function in momentum space for a wave with definite momentum. The integral from -1 to 1 of this function of 1 over x is zero. An infinite series of evenly spaced ones is called a (*) comb, and the Fourier transform of that construct is another comb. The convolution of a function with this one simply yields the original function. It was first rigorously defined mathematically by Laurent Schwartz. The integral of a function "f" multiplied by this function centered at point "a" is f(a) ("f of a"), and it is the derivative of a step function named after Heaviside. For 10 points, name this "improper" function with zero width, infinite height, and area one, often used to describe a sharp impulse.
Science