Tests for the internal quantum numbers of partons

The restrictions for the structure functions of deep-inelastic electroproduction and neutrino-induced production following from assigning partons to any representation of SU(2)×SU(2)×Y are derived. Apart from the general parton-model assumptions only isospin invariance and positivity are used. Comparison with experiment allows us to exclude all models which have only partons of spin \textonehalf{}, isospin ≤\textonehalf{}, and integral charge.