Syntax of Arithmetic Expressions

     X --> variable                { domain variable }
     
     N --> integer
     
     LinExpr --> N                { linear expression }
       |   X
       |   N * X
       |   N * N
       |   LinExpr + LinExpr
       |   LinExpr - LinExpr
     
     Expr --> LinExpr
       |   Expr + Expr
       |   Expr - Expr
       |   Expr * Expr
       |   Expr / Expr                { integer division }
       |   Expr mod Expr
       |   min(Expr,Expr)
       |   max(Expr,Expr)
       |   abs(Expr)
     
     RelOp --> #= | #\= | #< | #=< | #> | #>=