2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/50940Frames normal for linear connections in vector bundles are defined and studied. In particular, such frames exist at every fixed point and/or along injective path. Inertial frames for gauge fields are introduced and on this ground the principle of equivalence for (system of) gauge fields is formulated.20 standard LaTeX pages. The packages AMS-LaTeX and amsfonts are required. For related works, visit the publication pages at http://theo.inrne.bas.bg/~bozho/High Energy Physics - TheoryGeneral Relativity and Quantum CosmologyMathematical PhysicsNormal frames for linear connections in vector bundles and the equivalence principle in classical gauge theoriestext