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00925njm 22002777a 4500 dc Gallardo Gutiérrez, Eva Antonia author González, María J. author Nieminen, Pekka J. author Saksman, Eero author 2008 We show that there exist non-compact composition operators in the connected component of the compact ones on the classical Hardy space H-2. This answers a question posed by Shapiro and Sundberg in 1990. We also establish an improved version of a theorem of MacCluer, giving a lower bound for the essential norm of a difference of composition operators in terms of the angular derivatives of their symbols. As a main tool we use Aleksandrov-Clark measures. Gallardo Gutiérrez, E. A., et al. «On the Connected Component of Compact Composition Operators on the Hardy Space». Advances in Mathematics, vol. 219, n.o 3, octubre de 2008, pp. 986-1001. DOI.org (Crossref), https://doi.org/10.1016/j.aim.2008.06.005. 0001-8708 10.1016/j.aim.2008.06.005 https://hdl.handle.net/20.500.14352/50595 https//doi.org/10.1016/j.aim.2008.06.005 http://www.sciencedirect.com/science/article/pii/S0001870808001564 On the connected component of compact composition operators on the Hardy space