(we.ht the circumstances of their study. y*al nomenclature in England underIvji1 a change with the passing of the ntal Health Act, 1959. This not only changed "mental deficiency" into "mental subnormality" and did away with the terms "idiot", "imbecile" and "feeble-minded" (roughly replacing the first two by the severely subnormal and the last by the subnormal), but it "cured" those previously ...

Subnormal operators arise naturally in complex function theory, differential geometry, potential theory, and approximation theory, and their study has rich applications in many areas of applied sciences as well as in pure mathematics. We discuss here some research problems concerning the structure of such operators: subnormal operators with finite-rank self-commutator, connections with quadratu...