Fixed-Charge Transportation Problem: Facets of the Projection Polyhedron
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Bibliographic record
Abstract
In this paper we consider the well-known fixed-charge transportation problem. To send any flow from source s i to destination t j , we incur a unit variable shipping cost of c ij and a fixed cost f ij . Here we study the structure of the projection polyhedron of this problem, in the space of 0-1 variables associated with fixed charges, and we develop several classes of valid inequalities and derive conditions under which they are facet defining. In some cases, if the conditions are not satisfied, we show how they can be lifted to define facets. Several heuristics for generating and adding these facets are presented. Using these results, we develop a computationally effective algorithm for solving the problem. The computational results clearly indicate the usefulness of this approach.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it