Robert Lewis

Research Student (Part-time)

I studied mathematics at Oxford University as an undergraduate (1973-1976) followed by a masters in operational research at Lancaster University (1976-1977). Then I joined Shell in London for a career that included assignments in the Netherlands, Greece and Chile. In 2009 I started studying part-time for an MSc in mathemtics with the Open University which I completed in 2013. In that same year I retired from Shell and was accepted to study part-time with the Open University for a PhD in mathematics in an area of algebraic graph theory under Professor Jozef Siran.

I am in my first year studying part-time for a PhD in an area of algebraic graph theory. The PhD title is "Analysis and construction of extremal highly-symmetric graphs with given metric properties". So far I have been focusing on the degree-diameter problem for circulant graphs, being undirected Cayley graphs of cyclic groups. I have discovered a family of graphs of degree 8 and another of degree 9 for arbitrary diameter which are conjectured to be extremal for all diameters above a low threshold. This is currently being written up as an article for publication. I am trying to extend this result to families of graphs of higher degree.

Associated with:

Pure Mathematics

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