2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47225The catalysis of chiral symmetry breaking in the massless weakly coupled QED in a magnetic field is studied. It is shown that the effect is due to the dimensional reduction $D\to D-2$ in the dynamics of fermion pairing in a magnetic field. The dynamical mass of fermions (energy gap in the fermion spectrum) is determined. The temperature of the symmetry restoration is estimated analytically.6 pages. REVTeX. The talk given at the International Workshop "Mathematical Physics - today, Priority Technologies -- for tomorrow" (May 12-17, 1997, Kiev, Ukraine) and at the International School of Subnuclear Physics "Highlights: 50 Years Later" (Aug 26 - Sep 4, 1997, Erice-Sicily). The talk is based on a series of papers done in collaboration with V.P.Gusynin and V.A.MiranskyHigh Energy Physics - Phenomenologytext