Its main characteristics are as follows: (1) The objective function is a maximization type; (2) All constraints are equations; (3) The constants at the right end of the constraint equation are all nonnegative; (4) All decision variables are non-negative.

1. Linear programming model refers to a special mathematical programming model, that is, the objective function and constraint conditions are linear functions, linear equations or linear inequalities of variables to be solved.

2. A special mathematical programming model, that is, a mathematical programming model whose objective function and constraint conditions are linear functions, linear equations or linear inequalities of variables to be solved. It can be used to solve extreme value problems in various fields. The typical problem it describes is how to allocate limited resources in the best way in various activities.