# School of Mathematics

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## Prof S Barry Cooper

Professor of Pure Mathematics

Pure Mathematics

### Contact details

Room: ECS 7.59

Tel: +44 (0)113 3435165

Email: S.B.Cooper @ leeds.ac.uk

### Keywords

Mathematical logic

Computability theory

Foundations of science

Definability in the real world

Physics and computability

Emergence

Computational informatics

## Research interests

I am interested in the computational content of causality in the real world, particularly in the physical, mental and social contexts. Einstein said in 1950: "When we say that we understand a group of natural phenomena, we mean that we have found a constructive theory which embraces them".

Of the various ways of computably modelling causality in science, the best known is that of Turing reducibility. Allowing computation between real numbers using oracles, this is sufficient to capture the basics of familiar physical frameworks, such as that of Newtonian dynamics. One can generalise the notion to deal with computation relative to incomplete information via non-deterministic Turing machines, leading to a notion of enumeration reducibility. These reducibilities lead to quite beautiful and richly complex mathematical structures, termed the Turing and enumeration degrees, respectively. A main research interest is the ongoing project of characterising the structure of the Turing and enumeration degrees, locating basic real-world information within the structures, and furthering our understanding of the real-world consequences, at both the local and global levels.

I am President of the Association Computability in Europe, author of the standard text 'Computability Theory', Chair of the Turing Centenary Advisory Committee, a Managing Editor of the journal 'Computability', and an Advisor to the John Templeton Foundation.

### Useful links

Personal homepage for S Barry Cooper

Association Computability in Europe

Alan Turing Year

COMPUTABILITY, journal of the Association CiE

## Postgraduate students

Ingram Bondin (2013)

James Gay (2012)

James Riley (2012)

Daoud Siniora (2013)

David Toth (2014)

## Selected publications

S. Barry Cooper: The Incomputable Reality, Nature, 482 (23 February 2012), 465.

S. Barry Cooper: Turing's Titanic Machine? Communications of the ACM, 55 (3) (March 2012), 74-83.

S. Barry Cooper and Jan van Leeuwen: Alan Turing - His Work and Impact, Elsevier, Amsterdam, London, New York, 2013.

S. Barry Cooper: Incomputability after Alan Turing, Notices of the American Mathematical Society, 59(6) (June/July 2012), 776-784.

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