Algebraic and Topological Persistence

TL;DR

This thesis develops a rigorous mathematical foundation for algebraic and topological persistence, clarifying existing theories and extending them to triangulable spaces, with applications to filtrations of point clouds.

Contribution

It provides a canonical, rigorous presentation of persistence theory for triangulable spaces, filling gaps in the existing literature and clarifying foundational relationships.

Findings

Proves the Excision Theorem in algebraic topology.

Demonstrates the equivalence of simplicial and singular homology for triangulable spaces.

Develops the theory of persistent homology and cohomology for filtrations.

Abstract

This thesis addresses the theory of topological spaces and the foundations of persistence theory. We will discuss chain complexes and the associated simplicial homology groups, as well as their relationship with singular homology theory. Moreover, we present the fundamental concepts of algebraic topology, including exact and short exact sequences and relative homology groups derived from quotienting with subspaces of a topological space. These tools are used to prove the Excision Theorem in algebraic topology. Subsequently, the theorem is applied to demonstrate the equivalence of simplicial and singular homology for triangulable topological spaces, i.e. those topological spaces which admit a simplicial structure. This enables a more general theory of homology to be adopted in the study of filtrations of point clouds. The chapter on homological persistence makes use of these tools throughout. We develop the theory of persistent homology, the homology of filtrations of topological spaces, and the corresponding dual concept of persistent cohomology. This work aims to provide mathematicians with a robust foundation for productive engagement with the aforementioned theories. The majority of the proofs have been rewritten to clarify the relationships between the techniques discussed. The novel aspect of this contribution is the canonical presentation of persistence theory and the associated ideas through a rigorous mathematical treatment for triangulable topological spaces and closing some gaps in the existing literature.