2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/90274The paper presents a detailed theoretical-group analysis of three types of two-component equations of motion which describe the particle with zero mass and spin 1/2. There are studied P-, T- and C-propertias of the equations obtained.12 pagesQuantum PhysicsMathematical PhysicsExactly Solvable and Integrable Systemstext