2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/119099This is a revision and update of the part of the preprint math.CO/0405210 concerning field coefficients, line complexes, and the Hessian arrangement. The material from that paper concerning coefficients in arbitrary commutative rings and the deleted B_3 arrangement will appear separately.Revised version of part of math.CO/0405210CombinatoricsAlgebraic Geometry52C35; 16S99,14J26,05B35text