# Definition:Standard Lagrangian

## Definition

Let $P$ be a physical system composed of countable number of particles.

Let $L$ be a Lagrangian of $P$.

Let:

$L = T - V$

where $T$ is the kinetic energy and $V$ the potential energy of $P$.

Then $L$ is the Standard Lagrangian of $P$.

## Source of Name

This entry was named for Joseph Louis Lagrange.