Elementary Symmetric Function/Examples/m = 0

Example of Elementary Symmetric Function: $m = 0$
Let $e_0 \left({\left\{ {x_1, x_2, \ldots, x_n}\right\} }\right)$ be an elementary symmetric function in $n$ variables of degree $0$.

Then:
 * $e_0 \left({\left\{ {x_1, x_2, \ldots, x_n}\right\} }\right) = 1$

Proof
By definition:

Whether the summation $\displaystyle \sum_{1 \mathop \le n}$ makes sense, as such, is a moot point.