Definition:Product of Differences

Definition
Let $$n \in \Z, n > 0$$ be an integer.

Then $$\Delta_n \left({x_1, x_2, \ldots, x_n}\right)$$ is defined as:
 * $$\Delta_n = \prod_{1 \le i < j \le n} \left({x_i - x_j}\right)$$

Thus $$\Delta_n$$ is the product of the difference of all pairs of $$\left\{{x_1, x_2, \ldots, x_n}\right\}$$ where the index of the first is less than the index of the second.