‎Difference of weighted composition operator from Cauchy transform space into Dirichlet ‎space

Document Type : Original Paper

Author

Department of Mathematics, Mahabad Branch, Islamic Azad University, Mahabad, Iran

Abstract

‎‎‎‎‎Let $H(\mathbb{D})$ be the space of all analytic functions on $\mathbb{D}$‎, ‎$u,v\in H(\mathbb{D})$ and $\varphi,\psi$ be self-map $(\varphi,\psi:\mathbb{D}\rightarrow \mathbb{D})$‎. Difference of weighted composition operator is denoted by $uC_\varphi‎ -‎vC_\psi$ and defined as follows‎ ‎\begin{align*}‎ (uC_\varphi‎ -‎vC_\psi)f(z) = u(z) f{(\varphi(z))}‎- ‎v(z) f(\psi(z))‎ ,‎\quad f\in H(\mathbb{D} )‎, ‎\quad z\in \mathbb{D}‎. ‎\end{align*}‎ ‎In this paper‎, ‎boundedness of difference of weighted composition operator from Cauchy transform into Dirichlet space will be considered and ‎an ‎equivalence condition for boundedness of such operator will be given‎.‎‎ Then the norm of composition operator between the mentioned spaces will be studied and it will be shown ‎that‎‎ $\|C_\varphi\|\geq 1$ ‎and‎ there is no composition isometry from Cauchy transform into Dirichlet ‎space‎.‎

Keywords

Main Subjects


[۱ [عباسی، ابراهیم، نصراصفهانی، سپیده و خلیل پور، کمال، ۱۴۰۰ .عملگر استویچ شارما از فضای بسوف به فضای زیگموند. مجله مدلسازی
doi:۱۹۳۰ .۳۷۳۶۹ .۲۰۲۱/jamm. ۲۲۰۵۵ .۱۰ .۵۸۴ ‐ ۵۷۳ .صص)، ۱۱)۳ ،ریاضی پیشرفته
[۲ [نصراصفهانی، سپیده، حسنلو، مصطفی و عباسی، ابراهیم، ۱۴۰۱ .اندازه کارلسون و انواع عملگرهای ترکیبی روی فضاهای از نوع بسوف
doi:۱۹۷۴ .۳۸۹۱۸ .۲۰۲۲/jamm. ۲۲۰۵۵ .۱۰ .۱۲ ‐ ۱ .صص)، ۱۲)۱ ،ریاضی پیشرفته مدلسازی مجله. مقدار بردار دار وزن
[3] Li, S., Abbasi, E. and Vaezi, H., 2020. Weighted composition operators from Bloch­type spaces to nth weighted­type spaces. Annales Polonici Mathematici, 124, pp. 903­107. doi.org/10.4064/ap181119­3­4
[4] Abbasi, E., Li, S. and Vaezi, H., 2020. Weighted composition operators from the Bloch space to nthweighted­type, Turkish Journal of Mathematics, 44(1), pp. 108­117. doi.org/10.3906/mat­1907­34
[5] Abbasi, E. and Hassanlou, M., 2024. Generalized Stević­Sharma type operators on spaces of fractional Cauchy transforms. Mediterr. J. Math., 21(1), pp. 40. doi.org/10.1007/s00009­023­02583­z
[6] Allen, R. F. and Colonna, F., 2009. Isometries and spectra of multiplication operators on the Bloch space. Bulletin of the Australian Mathematical Society, 79, pp. 147­160.
doi:10.1017/S0004972708001196
[7] Allen, R. F. Heller, K. C. and Pons, M. A., 2014. Isometric composition operators on the analytic Besov spaces. Journal of Mathematical Analysis and Applications, 414 (1), pp. 414–423.
doi.org/10.1016/j.jmaa.2013.12.053
[8] Colonna, F., 2005. Characterisation of the isometric composition operators on the Bloch spaces. Bull. Austral. Math. Soc., 72, pp. 283–290. doi.org/10.1017/S0004972700035073
[9] Choa, J. S. and Kim, H. O., 2001. Composition operators from the space of Cauchy
transforms into its Hardy­type subspaces. Rocky Mountain J. Math., 31(1), pp. 95–113.
http://www.jstor.org/stable/44238557.
[10] Cima, J. A., Matheson, A. and Ross, W. T., 2004. The Backward Shift on the Space of Cauchy
Transforms. Proc. Amer. Math. Soc., 132 (3), pp. 745–54. S 0002­9939(03)07103­X
[11] Cima, J. A., Matheson, A. and Ross, W. T., 2006. The Cauchy transform. Mathematical Surveys and Monographs. 125. Providence, RI: American Mathematical Society.
[12] Dai, J., 2019. Topological structure of the set of composition operators on the weighted
Bergman space. Journal of Mathematical Analysis and Applications, 473(4), pp. 444–467.
doi.org/10.1016/j.jmaa.2018.12.060
[13] El­Gebeily, M. and Wolfe, J., 1985. Isometries of the disc algebra. Proc. Amer. Math. Soc., 93(4), pp. 697–702. doi.org/10.2307/2045547
[14] Forelli, F., 1964. The isometries of Hp. Can. J. Math., 16, pp. 721–728. doi.org/10.4153/CJM­1964­068­3
[15] Guo, X. and Wang, M., 2020. Linear combination of composition operators on Cauchy transform type spaces. Science China Mathematics, 50(12), pp. 1733–1744. doi:10.1360/SSM­2020­0160
[16] Hibschweiler, R. A. and MacGregor, T. H., 2006. Fractional Cauchy Transforms. Chapman and Hall. Boca Raton, FL: CRC.
[17] Hibschweiler, R. A., 2012. Composition operators on spaces of fractional Cauchy transforms. Complex Analysis and Operator Theory, 6(4). pp. 897–911. doi.org/10.1007/s11785­010­0104­3
[18] Hornor, W. and Jamison, J., 2001. Isometries of some Banach space of analytic functions. Integral Equations and Operator Theory, 41, pp. 410–425. doi.org/10.1007/BF01202102
[19] Hosokawa, T. and Ohno, S., 2006. Topological structures of the sets of composition operators on the Bloch spaces. J. Math. Anal. Appl., 314. pp. 736–748. doi:10.1016/j.jmaa.2005.04.080
[20] Maccler, B., Ohno, S. and Zhao, R., 2001. Topological structure of the space of composition operators on H∞. Integral Equations and Operator Theory, 40(4), pp. 481­494. doi.org/10.1007/BF01198142
[21] MacGregor, T. H., 1999. Fractional Cauchy transforms. Journal of Computational and Applied Mathematics, 105, pp. 93–108. doi.org/10.1016/S0377­0427(99)00022­9
[22] Saukko, E., 2011. Difference of composition operators between standard weighted Bergman spaces. J. Math. Anal. Appl., 381, pp. 789–798. doi.org/10.1016/j.jmaa.2011.03.058
[23] Shapiro, J. and Sundberg, C., 1990. Isolation amongst the composition operators. Pac. J. Math., 145(1). 117–152. doi: 10.2140/pjm.1990.145.117
[24] Sharma, A. Krishan, R. and Subhadarsini, E., 2017. Difference of composition operators from the space of Cauchy integral transforms to Bloch­type spaces. Integral Transforms and Special Functions, 28(2), pp. 145–155. doi.org/10.1080/10652469.2016.1255608
[25] Shi, Y. and Li, S., 2017. Essential norm of the differences of composition operators on the Bloch space. Math. Inequal. Appl., 20(2), pp. 543–555. doi: 10.7153/mia­20­37
[26] Shi, Y., Li, S. and Zhu, X., 2021. Difference of weighted composition operators from H∞ to the
Bloch space. Bullet. Iran. Math. Soc., 47(4). pp. 1245­1259. doi.org/10.1007/s41980­020­00439­w
[27] Shi, Y., Qu, D. and Li, S., 2022. Difference of composition operators on weighted Bergman spaces with doubling weights. Comput. Meth. Funct. Theory, 22(2). pp. 287­305. doi.org/10.1007/s40315021­00382­9
[28] Shi, Y. and Li, S., 2024. Difference of composition­differentiation operators from Hardy spaces
to weighted Bergman spaces via harmonic analysis. Bulle. des Sci. Math., 191, pp. 103383.
doi.org/10.1016/j.bulsci.2024.103383
[29] Stevic, S., 2024. Norm of the general polynomial differentiation composition operator from the space of Cauchy transforms to the mth weighted­type space on the unit disk. Math. Meth. the Appl. Scie., 47, pp. 3893­3902. doi: 10.1002/mma.9681
[30] Wang, M. and Guo, X., 2018. Difference of differentiation composition operators on the
fractional Cauchy transforms spaces. Num. Func. Anal. Optim., 39. pp. 1291–1315. doi:
10.1080/01630563.2018.1477798
[31] Zhao, R., 2010. Essential norms of composition operators between Bloch type spaces, Proc. Amer. Math. Soc., 138(7), pp. 2537­2546. S 0002­9939(09)09961­4