Could one define a production function which is homogenous as having constant elasticity of substitution. Just want clarification . Thanks
I'm answering if there is any production function which is homogeneous and CES too.
How about a CES production function only.
$y=(x^\rho +y^\rho )^\frac{1}{\rho }$ for $0\neq \rho <1$
This function has Elasticity of Substitution : $\sigma =\frac{1}{(1-\rho )}$ which is a constant.
Considering homogeneity,
$ y=((\lambda x)^\rho +(\lambda y)^\rho )^\frac{1}{\rho }$
$y=(\lambda^\rho (x^\rho +y^\rho ))^\frac{1}{\rho }$
$y=(\lambda ^\rho )^\frac{1}{\rho }(x^{\rho }+y^\rho )^\frac{1}{\rho }$
$y=\lambda (x^\rho +y^\rho )^\frac{1}{\rho }$ which is the initial production function.
Since, the degree of $\lambda $ is 1, so, it's homogeneous of degree $1$.