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\begin{document}$$1\leqslant p<\infty $$\end{document}, 0<q<∞\documentclass[12pt]{minimal}
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\begin{document}$$0<q<\infty $$\end{document}, and ν\documentclass[12pt]{minimal}
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\begin{document}$$\nu $$\end{document} be a two-sided doubling weight satisfying sup0⩽r<1(1-r)q∫r1ν(t)dt∫0rν(s)(1-s)qds<∞.\documentclass[12pt]{minimal}
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\begin{document}$$\begin{aligned} \sup _{0\leqslant r<1}\frac{(1-r)^q}{\int _r^1\nu (t)\,dt}\int _0^r\frac{\nu (s)}{(1-s)^q}\,ds<\infty . \end{aligned}$$\end{document}The weighted Besov space Bνp,q\documentclass[12pt]{minimal}
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\begin{document}$$\mathcal {B}_{\nu }^{p,q}$$\end{document} consists of those f∈Hp\documentclass[12pt]{minimal}
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\begin{document}$$f\in H^p$$\end{document} such that ∫01∫02π|f′(reiθ)|pdθq/pν(r)dr<∞.\documentclass[12pt]{minimal}
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\begin{document}$$\begin{aligned} \int _0^1 \left( \int _{0}^{2\pi } |f'(re^{i\theta })|^p\,d\theta \right) ^{q/p}\nu (r)\,dr<\infty . \end{aligned}$$\end{document}Our main result gives a characterization for f∈Bνp,q\documentclass[12pt]{minimal}
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\begin{document}$$f\in \mathcal {B}_{\nu }^{p,q}$$\end{document} depending only on |f|, p, q, and ν\documentclass[12pt]{minimal}
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\begin{document}$$\nu $$\end{document}. As a consequence of the main result and inner-outer factorization, we obtain several interesting by-products. For instance, we show the following modification of a classical factorization by F. and R. Nevanlinna: If f∈Bνp,q\documentclass[12pt]{minimal}
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\begin{document}$$f\in \mathcal {B}_{\nu }^{p,q}$$\end{document}, then there exist f1,f2∈Bνp,q∩H∞\documentclass[12pt]{minimal}
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\begin{document}$$f_1,f_2\in \mathcal {B}_{\nu }^{p,q} \cap H^\infty $$\end{document} such that f=f1/f2\documentclass[12pt]{minimal}
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\begin{document}$$f=f_1/f_2$$\end{document}. Moreover, we give a sufficient and necessary condition guaranteeing that the product of f∈Hp\documentclass[12pt]{minimal}
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\begin{document}$$f\in H^p$$\end{document} and an inner function belongs to Bνp,q\documentclass[12pt]{minimal}
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\begin{document}$$\mathcal {B}_{\nu }^{p,q}$$\end{document}. Applying this result, we make some observations on zero sets of Bνp,p\documentclass[12pt]{minimal}
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\begin{document}$$\mathcal {B}_{\nu }^{p,p}$$\end{document}.