Symbols:Greek

Product of Differences
$$\Delta_n \left({x_1, x_2, \ldots, x_n}\right)$$

Let $$n \in \Z, n > 0$$.

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.

The LaTeX code for $$\Delta_n \left({x_1, x_2, \ldots, x_n}\right)$$ is \Delta_n \left({x_1, x_2, \ldots, x_n}\right).

Kronecker Delta
$$\delta_{x y}$$

See Kronecker Delta.

The LaTeX code for $$\delta_{x y}$$ is \delta_{x y}.