2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/45192In this talk~\footnote{Talk presented at the IFT Workshop on Yukawa Couplings, Gainesville, FL, February 1994.} I summarize published work on a systematic operator analysis for fermion masses in a class of effective supersymmetric SO(10) GUTs \cite{adhrs}~\footnote{This work is in collaboration with G. Anderson, S. Dimopoulos, L.J. Hall, and G. Starkman.}. Given a minimal set of four operators at $M_G$, we have just 6 parameters in the fermion mass matrices. We thus make 8 predictions for the 14 low energy observables (9 quark and charged lepton masses, 4 quark mixing angles and $\tan β$). Several models, i.e. particular sets of dominant operators, are in quantitative agreement with the low energy data. In the second half of the talk I discuss the necessary ingredients for an SO(10) GUT valid below the Planck (or string) scale which reproduces one of our models. \footnote{These are preliminary results of work in progress with Lawrence Hall.} This complete GUT should still be interpreted as an effective field theory, i.e. perhaps the low energy limit of a string theory.}31 pages, Ohio State Univ. Preprint - OHSTPY-HEP-T-94-010 (figures may be obtained on request)High Energy Physics - Phenomenologytext