The 2-Modular and 3-Modular Decomposition Numbers for the Sporadic Simple O'Nan Group and its Triple Cover
Christoph Jansen, Robert Arnott Wilson · Journal of the London Mathematical Society · 1998
The 2-modular and 3-modular decomposition numbers for the sporadic simple O'Nan group O'N and its triple cover are determined. The results are obtained with the help of the computer algebra packages MeatAxe and GAP. Permutation modules and tensor products of modules have been condensed. The result relies on the construction of a 153-dimensional representation for 3·O'N over GF(4) and a 154-dimensional representation for O'N over GF(3).