According to my understanding, we should put a slack variable to equate an inequality constraint by inserting the slack variable in the side that is less than the other side. For example, if we have $4x+2<2$ this will be $4x+2+\text{slack_variable}=2$.

But in the example section of the Slack Variable Wikipedia, it says the following:

By introducing the slack variable $y\ge0$, the inequality $Ax\le b$ can be converted to the equation $y-Ax+b = 0$.

Which means that the slack variable is inserted on the bigger side! Please someone explain this confusion.

  • 6
    $\begingroup$ The Wikipedia example is wrong. It should be $Ax+y=b$. $\endgroup$
    – RobPratt
    Apr 7, 2020 at 3:20
  • 2
    $\begingroup$ FYI, I just fixed the Wikipedia entry. $\endgroup$
    – prubin
    Apr 7, 2020 at 22:15
  • $\begingroup$ Many thanks for all of you . $\endgroup$
    – John adams
    Apr 7, 2020 at 22:52


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.