## University of Western Ontario - Electronic Thesis and Dissertation Repository

#### Location of Thesis Examination

Room 2390 Support Services Building

#### Degree

Doctor of Philosophy

Mathematics

Graham Denham

1

#### Abstract

Drawing parallels with the theory of hyperplane arrangements, we develop the theory of arrangements of submanifolds. Given a smooth, finite dimensional, real manifold $X$ we consider a finite collection $\A$ of locally flat codimension $1$ submanifolds that intersect like hyperplanes. To such an arrangement we associate two posets: the \emph{poset of faces} (or strata) $\FA$ and the \emph{poset of intersections} $L(\A)$. We also associate two topological spaces to $\A$. First, the complement of the union of submanifolds in $X$ which we call the \emph{set of chambers} and denote by $\Ch$. Second, the complement of union of tangent bundles of these submanifolds inside $TX$ which we call the \emph{tangent bundle complement} and denote by $M(\A)$. Our aim is to investigate the relationship between combinatorics of the posets and topology of the complements.

We generalize the Salvetti complex construction in this setting and also charcterize its connected covers using incidence relations in the face poset. We also demonstrate some calculations of the fundamental group and the cohomology ring. We apply these general results to study arrangements of spheres, projective spaces, tori and pseudohyperplanes. Finally we generalize Zaslavsky's classical result in order to count the number of chambers.

COinS