The AND aggregation operator evaluates the logical expression logic-expression jointly for each member of the index set index-set. The index set enumeration finishes early if the logic-expression evaluation produces a false value (zero or missing). The expression returns 0 if a false value is found or returns 1 otherwise. The following code demonstrates both a true and a false result:

proc optmodel;
   put (and{i in 1..5} i < 10); /* returns 1 */
   put (and{i in 1..5} i NE 3); /* returns 0 */