Alias

One device used in the economic equilibrium formulation is the so called alias command that allows us to have a second name for the same set allowing us, in that case, to consider both the effects of own and cross commodity quantity on the demand and supply price for an item.  Then general form of an Alias is

ALIAS(knownset,newset1,newset2,...);

where each of the new sets will refer to the same elements as in the existing knownset.

More on alias appears in the Sets chapter.