Cauchy-Bunyakovsky-Schwarz Inequality

Cauchy's Inequality
The special case of the Cauchy-Bunyakovsky-Schwarz Inequality in a Euclidean space is called Cauchy's Inequality.

It was who first published this result in $1821$.

It is usually stated as:

Also known as
This theorem is also known as the Cauchy-Schwarz inequality or just the Schwarz inequality.