# Tag Info

## Hot answers tagged reduced-costs

### Must the Newly Generated Column be used in RMP in the Column Generation Method?

I assume that you are minimizing. If you only add one column at a time, the new column should immediately enter the basis. If you add multiple columns with negative reduced costs before doing more ...
• 37.9k
Accepted

### Can one strengthen the Lagrangian dual bound in column generation when there are multiple subproblems?

Yes, that bound is valid, and you can prove it by exhibiting a dual feasible solution with that objective value. I don’t have my copy handy, but Wolsey’s Integer Programming shows this. In fact, the ...
• 30.5k
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### Reduced cost fixing for binary programs

Assume you want to solve $$\begin{array}{ll} min & c^T x \\ st & A x = b \\ & x \geq 0 \end{array}$$ For any dual feasible solution $(\hat y,\hat s)$ it holds  \hat s = c - A^T \...
• 3,046
1 vote
Accepted

### The dual values and change in the variables values

Let $\bar{A}$ and $\bar{x}$ be $A$ and $x$ augmented by slack variables, so that the constraints become $\bar{A} \bar{x} = b.$ The LP solution partitions $\bar{A} = [B N]$ (after permuting columns if ...
• 37.9k
1 vote
Accepted

### Understanding reduced costs and dual values

One of the best possible ways for the models with some difficulties to understand how the model can be treating in the solving process, specifically in the situations like infeasibility, comparing ...
• 8,450

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