Ring Operator Symbol

U+2218

\circ

In math, the ring operator symbol (∘) denotes function composition. Composing functions and produces a new function whose value is found by applying first and then :

The ring operator () should not be confused with the larger circle symbol (), which is rendered by the TeX command \bigcirc.

Circle (◯)

Geometry circle symbol.

Asterisk Operator (∗)

The asterisk operator is used in math to denote convolution operations between functions or signals. It represents the convolution of two functions, a fundamental operation in signal processing, image processing, and applied mathematics.