### Abstract

A comparability graph is a graph which admits a transitive orientation. In this paper we consider the problem of augmenting a graph to a comparability graph in such a way that the maximum weight of its cliques is minimum. The problem is equivalent to a multiprocessor scheduling problem and to the interval coloring problem; and in the unweighted case also to the chromatic number problem. In the general case, the problem is NP-hard in the strong sense even on some very simple types of perfect graphs. We give complexity and approximation results for two subclasses of perfect graphs, namely for split graphs and stars of cliques, for which the problem still remains intractable but admits efficient estimations.

Original language | English |
---|---|

Pages (from-to) | 71-84 |

Number of pages | 14 |

Journal | Discrete Applied Mathematics |

Volume | 72 |

Issue number | 1-2 |

Publication status | Published - Jan 10 1997 |

### Fingerprint

### Keywords

- Approximation results
- Comparability graphs
- Computational complexity
- Interval coloring
- Multiprocessor scheduling
- Split graphs

### ASJC Scopus subject areas

- Computational Theory and Mathematics
- Applied Mathematics
- Discrete Mathematics and Combinatorics
- Theoretical Computer Science

### Cite this

*Discrete Applied Mathematics*,

*72*(1-2), 71-84.

**Comparability graph augmentation for some multiprocessor scheduling problems.** / Dell'Olmo, P.; Speranza, M. Grazia; Tuza, Z.

Research output: Contribution to journal › Article

*Discrete Applied Mathematics*, vol. 72, no. 1-2, pp. 71-84.

}

TY - JOUR

T1 - Comparability graph augmentation for some multiprocessor scheduling problems

AU - Dell'Olmo, P.

AU - Speranza, M. Grazia

AU - Tuza, Z.

PY - 1997/1/10

Y1 - 1997/1/10

N2 - A comparability graph is a graph which admits a transitive orientation. In this paper we consider the problem of augmenting a graph to a comparability graph in such a way that the maximum weight of its cliques is minimum. The problem is equivalent to a multiprocessor scheduling problem and to the interval coloring problem; and in the unweighted case also to the chromatic number problem. In the general case, the problem is NP-hard in the strong sense even on some very simple types of perfect graphs. We give complexity and approximation results for two subclasses of perfect graphs, namely for split graphs and stars of cliques, for which the problem still remains intractable but admits efficient estimations.

AB - A comparability graph is a graph which admits a transitive orientation. In this paper we consider the problem of augmenting a graph to a comparability graph in such a way that the maximum weight of its cliques is minimum. The problem is equivalent to a multiprocessor scheduling problem and to the interval coloring problem; and in the unweighted case also to the chromatic number problem. In the general case, the problem is NP-hard in the strong sense even on some very simple types of perfect graphs. We give complexity and approximation results for two subclasses of perfect graphs, namely for split graphs and stars of cliques, for which the problem still remains intractable but admits efficient estimations.

KW - Approximation results

KW - Comparability graphs

KW - Computational complexity

KW - Interval coloring

KW - Multiprocessor scheduling

KW - Split graphs

UR - http://www.scopus.com/inward/record.url?scp=0043223773&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0043223773&partnerID=8YFLogxK

M3 - Article

VL - 72

SP - 71

EP - 84

JO - Discrete Applied Mathematics

JF - Discrete Applied Mathematics

SN - 0166-218X

IS - 1-2

ER -