Dr David Bevan


Mathematics and Statistics


Personal statement

I am a Lecturer in Combinatorics. My research interests concern enumerative, asymptotic and extremal questions, particularly in relation to permutations.

Enumerative combinatorics is concerned with counting, either exactly or approximately, the number of discrete structures satisfying certain constraints. Asymptotic combinatorics is to do with determining the structure and properties of typical large discrete objects. Extremal combinatorics concerns determining the size of the largest possible discrete structures of a given type.

Current topics of research include enumerative and structural questions concerning grid classes of permutations, the enumeration and structure of the class of permutations avoiding the pattern 1324, and how the structure of a random permutation evolves as the number of its inversions increases.

For more information about research in combinatorics at the University of Strathclyde, see the Strathclyde Combinatorics Group webpage.

A bit of background

In the 1980s, following undergraduate studies in mathematics at the University of Oxford, I undertook some computer science research. For my Oxford M.Sc. dissertation, I developed a model for the denotational semantics of the concurrent programming language occam. Following this, I spent two years in industry, during which I produced a paper that introduced weighted reference counting, now a key method for managing memory in distributed computer architectures.

This was followed by a career in software development, first as a developer, consultant and trainer in the voluntary sector, based in Papua New Guinea, and subsequently as a software engineer and development manager in industry in the UK.

In my spare time, I carried out some independent mathematical research resulting in the publication of a paper improving on a long-standing extremal result of Erdős and Füredi in discrete geometry. In 2012, I left software development for full-time mathematical research, and in 2015 was awarded a PhD from The Open University. The topic of my thesis was the growth of permutation classes. Following a year as a Visiting Research Fellow and Associate Lecturer at The Open University, I took up my current position in September 2016.


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Currently, I'm teaching the following:

MM109 Applying Mathematics 2: Graph Theory

Types of graphs; graph operations, walks on graphs; connectivity; Eulerian graphs; Hamiltonian graphs; algorithms for weighted graphs; trees and forests; spanning trees; planarity; colouring; matchings; digraphs; network flows.

MM917 Networks in Finance

Random networks; the small-world phenomenon; scale-free networks; the Barabási–Albert model; centrality; degree correlation; robustness; spreading; communities.

Past teaching responsibilities include the following:

MM116 Mathematics 1c (Semester 1)

Foundations; introduction to calculus.

CS103 Machines, Languages and Computation (Semester 2)

Propositional logic and proofs using natural deduction; normal forms and satisfiability; computational complexity, P and NP; finite state automata and regular expressions, the Brzozowski algebraic method and the pumping lemma; Turing machines, undecidability, the halting problem and the Entscheidungsproblem.

CS104 Information and Information Systems (Module 1: Information Theory)

Data and information (syntax and semantics, text encodings, Unicode and UTF-8); error detection and correction (repetition codes, parity bits and Hamming codes); data compression (run-length encoding and LZW); measuring information (entropy) and Shannon's Source Coding Theorem.

CS106 Computer Systems and Organisation (Semester 2)
CS107 Fundamentals of Computer Systems

Computer organization; MIPS assembly programming and the MIPS Instruction Set Architecture (registers, memory addressing, logical and shifting operations, jumps and branches, loops and arrays, integers and integer arithmetic, subroutines and the call stack, recursion); memory caching; virtual memory.

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Research Interests

My research interests concern aspects of enumerative, asymptotic and extremal combinatorics, particularly with relation to permutations.


Recent publications

My older publications can be found on the following pages: ORCiD / dblp / Scopus / Google Scholar

Slides from talks

Mathematica demonstrations


Professional Activities

Combinatorial Theory (Journal)
Peer reviewer
Pattern Avoidance, Statistical Mechanics and Computational Complexity
Scottish Combinatorics Meeting 2023
Permutation Patterns 2021 Virtual Workshop
Enumerative Combinatorics and Applications (Journal)
Guest editor
Pattern Avoidance, Statistical Mechanics and Computational Complexity

More professional activities


Maths DTP 2020 University of Strathclyde | Threlfall, Daniel
Bevan, David (Principal Investigator) Steingrimsson, Einar (Co-investigator) Threlfall, Daniel (Research Co-investigator)
01-Jan-2020 - 01-Jan-2024

More projects

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Dr David Bevan
Mathematics and Statistics

Email: david.bevan@strath.ac.uk
Tel: 548 4535