2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/168487In this paper we study two types of fibrations associated with a 3-dimensional unital associative irreducible algebra and their basic properties. We investigate trivial principal fibrations of degenerate semi-Euclidean sphere and their semi-conformal and projective models. We use Norden normalization method for constructing second model.11 pages, 1 figure; presented at 28th Winter School Geometry and Physics, Srni, Czech RepublicDifferential Geometrytext