A Short Course in Linear Programming

 

Lesson 6. Mathematics of LP

Use the Mathematical Programming Glossary to look up terms you do not understand. 

First, look at Theorems of the alternative in my glossary (pay special attention to those of Fourier, Farkas and Motzkin).

Second, read The Fundamental Theorems of Linear Programming, and see if you can prove them.

Third, look up the following terms in my glossary:

Exercises. Let  be a finite collection of m inequalities, and let M ={1,...,m}. Define the dual system: . The support set, , of a non-negative vector, v, is the set of indexes for which the coordinate is positive. In particular,  is the support set for y satisfying the dual system, and  is the set of rows with surplus for a solution, x, to S. Prove each of the following.
  1. x and y must satisfy complementary slackness: .

  2. Solution.
  3. If both S and  are consistent, there must exist a strictly complementary solution:  such that .

  4. Solution.
  5. If  and  are two strictly complementary solutions to S and , their partitions are the same: .

  6. Solution.
  7. S is inconsistent if, and only if,  is consistent. Further, let Y = {y: y satisfies Sd and yb > 0}, and suppose . Then,  is an IIS if, and only if, there does not exist  such that . (In the latter, such a y is called an elementary vector of Y.)

  8. Solution.
  9. Suppose S is consistent. Then,  is redundant in S if, and only if,  is consistent. This is strongly redundant if, in addition, yb > 0.

  10. Solution.
  11. Suppose S is consistent. Then,  is an implied equality of S if, and only if,  is consistent.

  12. Solution.

Last updated: March 24, 1997