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.



Threshold functions and the birthday paradox
Bevan David
Mathematical Gazette Vol 106, pp. 344-348 (2022)
Independence of permutation limits at infinitely many scales
Bevan David
Journal of Combinatorial Theory. Series A Vol 186 (2022)
Games of no chance 5 edited by Urban Larsson, pp 490, £110.00 (hard), ISBN 978-1-108-48580-7, Cambridge University Press (2019)
Bevan David
Mathematical Gazette Vol 105, pp. 569-570 (2021)
A structural characterisation of Av(1324) and new bounds on its growth rate
Bevan David, Brignall Robert, Elvey Price Andrew, Pantone Jay
European Journal of Combinatorics Vol 88 (2020)
Bijections between directed animals, multisets and Grand-Dyck paths
Baril Jean-Luc, Bevan David, Kirgizov Sergey
The Electronic Journal of Combinatorics Vol 27 (2020)
Permutations with few inversions are locally uniform
Bevan David
Discrete Analysis (2019)

More publications


Currently, I'm teaching the following:

MM116 Mathematics 1c (Semester 1)

Foundations; introduction to calculus.

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:

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.

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

Permutation Patterns 2021 Virtual Workshop
Enumerative Combinatorics and Applications (Journal)
Guest editor
Pattern Avoidance, Statistical Mechanics and Computational Complexity
Annals of Combinatorics (Journal)
Peer reviewer
Graphs and Combinatorics (Journal)
Peer reviewer
Algebraic Combinatorics (Journal)
Peer reviewer

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


Mathematics and Statistics
Livingstone Tower

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