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The index of a plane curve and green’s formula

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Abstract

In this paper we compute the line integral of a complex function on a rectifiable cycle homologous to zero obtaining a Green’s formula with multiplicities that involves the\(\bar \partial \) of the function and the index of the cycle. We consider this formula in several settings and we obtain a sharp version in terms of the Lebesgue integrability properties of the partial derivatives of the function. This result depends on the proven fact that the index of a rectifiable cycle is square integrable with respect to the planar Lebesgue measure.

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Correspondence to Joan Josep Carmona.

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The work of both authors is partially supported by grants 2000SGR-00059, 2001SGR 00172 of Generalitat de Catalunya and BFM 2002-04072-C02-02 of Ministerio de Ciencia y Tecnologia

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Carmona, J.J., Cufí, J. The index of a plane curve and green’s formula. Rend. Circ. Mat. Palermo 53, 103–128 (2004). https://doi.org/10.1007/BF02921431

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