Is there a name for this type of CES look-alike utility function? I do not know whether the following utility functions are used a lot but I was wondering whether there was a common name for this type CES like utility function
$$u(z) = \left[  \left( \sum_{j \in J_1} z_{j}^{\alpha_1}\right)^{\rho/\alpha_1} + \left(\sum_{j \in J_2} z_{j}^{\alpha_2}\right)^{\rho/\alpha_2} \right]^{1/\rho},$$
perhaps it is simply an instance of the CES?
The utility function is defined over two non-overlapping groups $J_1$ and $J_2$ of goods $z_j$. The goods from the two groups are weighted diffrently in the inner CES part by $\alpha_1$ and $\alpha_2$ respectively.
I believe it can be found as &quot;nested CES&quot;
See for example:
Nested CES