Heaviside theta function | unit step function

The Heaviside step function is a mathematical function denoted H(x), or sometimes θ(x) or u(x), and also known as the "unit step function." The term "Heaviside step function" and its symbol can represent either a piecewise constant function or a generalized function.

absolute value | boxcar function | delta function | ramp function | rectangle function | sigmoid function | sign | square wave | triangle function

Oliver Heaviside