Linear programming - simplex computational procedure, geometric interpretation, revised simplex method, duality, degeneracy, perturbation techniques - One Line Questions

1. If the primal problem is a minimization problem with 'greater than or equal to' constraints, its dual will be: A maximization problem with 'less than or equal to' constraints
2. What is the 'dual' of a linear programming problem? A problem derived from the original problem that provides information about the primal solution
3. The perturbation technique ensures that in each iteration of the simplex method: A unique variable leaves the basis
4. In the context of the simplex method, what does a 'basic feasible solution' represent? A vertex of the feasible region
5. What is a 'basic variable' in the context of the simplex method? A variable that is part of the basis and has a non-zero value
6. Which technique is commonly used to resolve degeneracy and prevent cycling in the simplex method? The perturbation technique (e.g., lexicographical method)
7. What is the 'optimality condition' for a minimization problem in the simplex method? All coefficients in the objective row (Cj - Zj) must be non-negative
8. The duality theorem in linear programming states that: If a primal problem has an optimal solution, so does its dual, and their optimal values are equal
9. If a linear programming problem has multiple optimal solutions, what is characteristic of its simplex tableau at optimality? At least one non-basic variable has a zero coefficient in the objective row
10. In the revised simplex method, how are the reduced costs (or objective function coefficients in the non-basic variables) calculated? Using the basis inverse and the original cost coefficients
11. The Big M method uses a large penalty (M) in the objective function to: Discourage the use of artificial variables in the optimal solution
12. The revised simplex method is computationally more efficient for problems with: A very large number of constraints
13. In the context of duality, what is the 'complementary slackness' condition? Both (A) and (B)
14. The 'fundamental theorem of duality' states that for any primal-dual pair of linear programming problems: If the primal is unbounded, the dual is unbounded
15. In the geometric interpretation, the simplex method moves from one vertex of the feasible region to an adjacent vertex by: Changing one non-basic variable to basic and one basic variable to non-basic
16. If a primal linear programming problem has no feasible solution, what can be said about its dual problem? It has an unbounded solution
17. Which of the following is a characteristic of the dual of a maximization problem? It is a minimization problem
18. When using the perturbation technique, how is a variable with a zero value handled? It is treated as having a very small positive value (epsilon)
19. What does the term 'degeneracy' imply about the basic feasible solution? It is at the intersection of more than the usual number of constraint boundaries
20. Which of the following is NOT a characteristic of the simplex method's tableau? It shows the current value of the objective function
21. If a primal problem has 'm' constraints and 'n' variables, its dual problem will have: n variables and m constraints
22. The revised simplex method is an efficient alternative to the standard simplex method primarily because it: Computes only the necessary elements of the tableau
23. What is the primary advantage of the revised simplex method over the standard simplex method for large-scale problems? Reduced storage requirements by avoiding explicit tableau construction
24. What is a potential problem caused by degeneracy during the simplex computation? The algorithm may cycle, returning to a previous basic feasible solution indefinitely
25. In the dual simplex method, which variable is selected to leave the basis? The basic variable with the most negative value
26. In a maximization problem, if all coefficients in the objective function row (Cj - Zj) of the simplex tableau are non-negative, what can be concluded? The current solution is optimal
27. What is the geometric interpretation of duality? The dual problem provides lower bounds for the primal maximization problem
28. The dual simplex method is particularly useful when: The initial solution is optimal but not feasible
29. What is the 'basis inverse' in the revised simplex method? The inverse of the submatrix formed by the basic variables
30. What does the geometric interpretation of the simplex method illustrate? The movement between vertices of the feasible region
31. The perturbation technique modifies the problem slightly to ensure that: All basic variables are strictly positive
32. The perturbation technique can be viewed as introducing a small positive quantity 'epsilon' to: The right-hand side values of the constraints
33. Degeneracy in linear programming occurs when: At least one basic variable in a basic feasible solution is zero
34. What do the values of the dual variables at the optimal solution represent? The shadow prices or marginal values of the resources
35. In the context of duality, if a dual variable is zero, what does it imply about the corresponding primal constraint? The primal constraint is non-binding (has slack)
36. Which method is often used to find an initial basic feasible solution for problems with no obvious origin solution? The Two-Phase Method or Big M Method
37. What does it mean for a constraint to be 'binding' at the optimal solution? The constraint is satisfied as an equality
38. What is the primary difference in approach between the standard simplex method and the revised simplex method? The standard method uses a tableau, while the revised method uses matrix inversions
39. What does the 'shadow price' of a resource represent in linear programming? The optimal value of the dual variable associated with the resource constraint
40. The 'pricing out' operation in the revised simplex method involves calculating: The reduced costs for the non-basic variables
41. What is the 'simplex criterion' for selecting the entering variable in a maximization problem? The variable with the most negative coefficient in the objective row
42. What is the purpose of 'slack variables' in linear programming? To convert inequality constraints into equality constraints
43. What is the role of the 'pivot element' in the simplex computational procedure? To determine the direction of movement to a new basic feasible solution
44. What is the primary goal of the simplex method in linear programming? To find the optimal solution to a linear programming problem
45. What is the purpose of 'artificial variables' in the simplex method? Both (B) and (C)
46. If the primal problem is unbounded, what is the status of the dual problem? Infeasible
47. When does a linear programming problem have an unbounded solution according to the simplex method? When an entering variable can be increased indefinitely without violating constraints
48. The 'ratio test' in the simplex method is used to determine: Which variable leaves the basis (the outgoing variable)