A binary operator symbol representing multiplication, convolution, or general binary operations in algebra and analysis.
Examples
Convolution operator
(f \ast g)(t) = \int_{-\infty}^{\infty} f(\tau)g(t-\tau)d\tau
Group operation notation
a \ast b = b \ast a \text{ for all } a,b \in G
Multiplication in a ring
R = \{a + b\sqrt{2} : a,b \in \mathbb{Z}\} \text{ under } + \text{ and } \ast