Data files


Covering designs and Hypergraphs

As part of my research work I have generated all uniform non-isomorphic hypergraphs, with the maximum number of hyperedges, avoiding certain subgraphs. For some of these avoided subgraphs this is equivalent to generating all non-isomorphic covering designs with given parameters. In many cases my results were the first to determine the size of optimal such designs.
Turan Hypergraphs
Covering designs
Double covering designs


Low discrepancy sequence for the Erös discrepcany problem


For the start of the Polymath5 project I have generated examples of sequnece with low dsicrpeancy along arithmetic progressions. These can be found on this page.

Extremal sets related to the Hales-Jewett theorem


As part of the Polymath1 project I generated various extremal sets. These can be found on this page.

The Ising polynomial for square grids

On this page you can find the Ising polynomials for Ck×Ck for k up to 320, a mathematica notebook for fast computation of such polynomials, and the reference to the accompanying paper.

Cubic graphs avoiding certain cycle lengths

I have generated all small cubic graphs not containing cycles of certain lengths. You can find the graphs here.
Other interesting cubic graphs can be found at The House of Graphs.

Boolean formulae constructed to challenge SAT-solvers

On this page I have some examples of boolean formulae generated to be hard for DPLL and resolution based satisfiabillity program to prove unsolvable. The page also includes a Mathematica notebook for generating such formulae from graphs.

The number of graphs

The number of graphs on n vertices, for n up to 68 txt
Just something that I computed when I was reading about a random graph generator which needed this as input.