Date of Publication

2009

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Mathematics

Subject Categories

Mathematics

College

College of Science

Department/Unit

Mathematics and Statistics Department

Thesis Adviser

Severino V. Gervacio

Defense Panel Member

Yvette F. Lim
Leonor A. Ruivivar
Blessilda P. Raposa
Isagani B. Jos
Erminda Fortes,

Abstract/Summary

The intersection graph of a non-empty family L of line segments in the plane, denoted by (L), is de ned as the graph whose vertex-set is L, where there is an edge between two vertices `1 and `2 in L if `1 \ `2 6= . If L is a family of half-lines, (L) is called a half-line intersection graph. We de ne here a graph whose half-line representation L can be contained in an arbitrarily thin -slice of the plane (the convex subset of R2 bounded by two half-lines with a common end-point and making an angle of (radians) with each other, 0 < < ) as wedge graphs. We show that wedge graphs are closed under the graph operations union and join. We prove that wedge graphs are segment intersection graphs and unit intersection graphs. We also determine the e ects of other graph operations such as cartesian product, conjunction, composition and power on some special graphs.

Abstract Format

html

Language

English

Format

Electronic

Accession Number

CDTG004564

Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

v, 71 leaves ; 28 cm.

Keywords

Intersection graph theory

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