A var_specification can be one of the following types:

variable <=[lower-bound <, upper-bound>]>

(variables) <=[lower-bound <, upper-bound>]>

The VARIABLE statement declares all variables that are to be considered in the CSP and, optionally, defines their domains. Any variable domains defined in a VARIABLE statement override the global variable domains that are defined by using the DOMAIN= option in the PROC CLP statement in addition to any bounds that are defined by using the CONDATA= data set. If lower-bound is specified and upper-bound is omitted, the corresponding variables are considered as being assigned to lower-bound. The values of lower-bound and upper-bound can also be specified as missing, in which case the appropriate values from the DOMAIN= specification are substituted.