Sections of Lefschetz fibrations and Stein fillings

Authors : Andras Stipsicz

Pages : 97-102

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :Using Eliashberg`s theorem about Stein fillings of S3 we prove that a section of a Lefschetz fibration over S2 has nonnegative square. This observation, in particular, implies that the identity element 1\in G g 1 in the mapping class group of a genus-g surface with one boundary component cannot be written as a product of positive Dehn twists.
Keywords : Turk J Math, 25, 2001, , 97 102 Turk J Math, vol 25, iss 1