Interpretation of Slack Variables - Definition Previous Next
Definition of the First Slack Variable
Let  denote the first slack variable for the first functional constraint.
Define
Require that .
Use of the First Slack Variable
With the above definition of the first slack variable , requiring that
is equivalent to requiring that
For any value of  and , the box forces  to have the value that satisfies its definition. If , then
 , and vice-versa.
 
The simplex method uses this box to replace the inequality constraint .