The variable in the RANGE statement, the ID variables, and the BY variables are available for the model program to examine, but their values should not be changed by the program.

It is shown that the integer linear programming problem with a fixed number of variables is polynomially solvable. The proof depends on methods from geometry of numbers.

Health programs that use social and related data obtained through surveys or other methods need to distinguish among so-called independent variables. Three groups of independent variables are (a) ...