Erratum to: Joint Hyponormality of Rational Toeplitz Pairs

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In Theorem 1 of the article “Joint Hyponormality of Rational Toeplitz Pairs” [1], the condition ‘φ and ψ have a common pole’ has to be assumed. Due to a technical problem, we omitted an assumption in Theorem 1 of [1]. For the sake of completeness, we restate Theorem 1, in its correct form. Theorem 1. Let φ and ψ be rational functions in L∞ which have a common pole. If T = (Tφ, Tψ) is hyponormal then φ− βψ ∈ H for some constant β. The proof of [1, Theorem 1] is correct and complete under the additional assumption ‘φ and ψ have a common pole.’ In turn, Corollary 2 of [1] should also have an additional assumption ‘θ0 and θ2 are not coprime,’ which is equivalent to the condition ‘φ and ψ have a common pole.’ We would remark that Corollary 2 of [1] is still a generalization of the case of trigonometric polynomial symbols because if φ and ψ are trigonometric (non-analytic) polynomials then they have a common pole at z = 0.