Errata to: ‘‘Norms of Hankel operators on a bidisc”

Abstract

The proof of Theorem 1 in [3] is true only for r = 0 and r = -oo. For if r $ 0 or r $7 -oo then {UJ'-O, ZjH2} is not a subspace. Since Ko wH @E z(H2 oo E H2), if g E K2 then g = g0 E g, when g0 E wH2 and gO0 E z(H2 e H2). Hence (qf, g) = (qff, g) + (qf, g_1O) for f E H2. This was suggested by the proof of Corollary 3 in [1]. Thus by Theorem 1 for r=0 and r=-oo in[3]andbythat H2xwH2cwH1 and H2xzH2 C zHI , the following is true clearly.