Some two-character sets

摘要

Some new examples of two-character sets with respect to planes of PG(3, q 2), q odd, are constructed. They arise from three-dimensional hyperbolic quadrics, from the geometry of an orthogonal polarity commuting with a unitary polarity. The last examples arise from the geometry of the unitary group PSU(3, 3) acting on the split Cayley hexagon H(2).