L'invariant de Calabi pour les homéomorphismes quasiconformes du disque

We prove that the Calabi invariant for the symplectic diffeomorphisms of the unit disk with compact support is well defined for quasiconformal maps and depends continuously with respect to these homeomorphisms in the quasiconformal topology. To cite this article: P. Ha??ssinsky, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 635–638.