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)