Let a product like

a1 * a2 * a3 * a4

be written like this :

PI(k from 1 to 4) ak

using the greek 'PI' symbol

Does anyone know if reversing the limits makes the product equal to 1 ?

(I suppose that for a sum, if the limits are in reverse order, sum = 0, no?)

Meaning that

PI(k from 4 to 1) = 1

cheers