Symmetry of sedeonic equations describing fields with zero and non-zero mass of quantum: Analysis based on space-time algebra

We investigate the symmetry of equations for fields with zero and non-zero mass of quantum within the framework of an algebraic approach based on the space-time sedeons. This method allows one to significantly compactify all relations describing the fields, as well as to highlight the symmetries of these relations. We show that the field equations are invariant with respect to a certain class of transformations, which are reduced to the action of the sedeonic operators responsible for the specific rotation in the space of fields and sources. Additionally we generalize the conditions of gauge (gradient) invariance of potentials, field strengths and sources for a wider class of scalar and vector functions. The main attention is paid to the symmetry analysis of the dyon model for the massless fields and the quadron model for fields with non-zero mass of quantum.