Domain variables

A domain expression is a list of integers or L..U which denotes a list of integers between L and U inclusive. The domains of variables are defined as follows:

		  domain(Vars,L,U) 

where Vars is one variable or a list of variables, and L and U are two integers which indicate the lower and upper bounds of the domain, respectively. Another way to define the domains of variables is as follows:

		  Vars in D 

where D is a domain expression.