Injections of Artin groups
Author(s) -
Robert W. Bell,
Dan Margalit
Publication year - 2007
Publication title -
commentarii mathematici helvetici
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.603
H-Index - 46
eISSN - 1420-8946
pISSN - 0010-2571
DOI - 10.4171/cmh/108
Subject(s) - mathematics , homeomorphism (graph theory) , injective function , homomorphism , braid group , modulo , outer automorphism group , group (periodic table) , automorphism , pure mathematics , mapping class group , combinatorics , artin group , automorphism group , surface (topology) , coxeter group , geometry , chemistry , organic chemistry
We study those Artin groups which, modulo their centers, are finite index subgroups of the mapping class group of a sphere with at least 5 punctures. In particular, we show that any injective homomorphism between these groups is given by a homeomorphism of a punctured sphere together with a map to the integers. The technique, following Ivanov, is to prove that every superinjective map of the curve complex of a sphere with at least 5 punctures is induced by a homeomorphism. We also determine the automorphism group of the pure braid group on at least 4 strands.
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