13C99 16D80 5 16U80 3 $J$-symmetric ring 2 11Y50 2 13C05 2 Jacobson radical 2 Rickart modules 2 abelian modules 2 faithful module 2 fitting ideals 2 multiplication module 2 principally projective modules 2 projective of constant rank 2 reduced modules 2 rigid modules 2 semicommutative modules 2 symmetric modules 2 symmetric ring 2 13C13 1 2-primal rings 1 Noetherian space 1 Spectral space 1 central Armendariz rings 1 central reduced rings 1 central reversible rings 1 central semicommutative rings 1 central symmetric rings 1 irreducible space 1 symmetric rings 1