2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49712The new quantum number is introduced. It is shown that the conservation of -number results in the conservation of difference between baryon and lepton numbers. The problem of quark-lepton symmetry is discussed. It is shown that the nature of quark-lepton symmetry stems from the fact that the particles of one generation are subject to the symmetry transformation represented by 4-group of diedr.5 pages, 1 figureHigh Energy Physics - Phenomenologytext