Amoroso–Robinson relation

The Amoroso–Robinson relation, named after economists Luigi Amoroso and Joan Robinson, describes the relation between price, marginal revenue, and elasticity of demand.

$\frac{\partial R}{\partial x}=p\left( 1%2B\frac{1}{\epsilon _{x,p}}\right)$ ,

where

$\scriptstyle \frac{\partial R}{\partial x}$ is the marginal revenue,
$x$ is the particular good,
$p$ is the good's price,
$\epsilon_{x,p}<0$ is the price elasticity of demand.

See also

Lerner index

References

Robinson, Joan (1932), "Imperfect Competition and Falling Supply Price", The Economic Journal 42 (168): 544–554, JSTOR 2223779