In this article, we study the maximal length of positive Dehn
twist factorizations of surface mapping classes. In connection to
fundamental questions regarding the uniform topology of symplectic
–manifolds and Stein fillings
of contact
–manifolds
coming from the topology of supporting Lefschetz pencils and open books, we
completely determine which boundary multitwists admit arbitrarily long positive Dehn
twist factorizations along nonseparating curves, and which mapping class groups contain
elements admitting such factorizations. Moreover, for every pair of positive integers
and
, we tell whether or
not there exist genus-
Lefschetz pencils with
base points, and if there are, what the maximal Euler characteristic
is whenever it is bounded above. We observe that only symplectic
–manifolds
of general type can attain arbitrarily large topology regardless of the genus and the
number of base points of Lefschetz pencils on them.
Keywords
mapping class groups, Lefschetz fibrations, contact
manifolds, symplectic manifolds
Department of Mathematics and
Statistics
University of Massachusetts
Lederle Graduate Research Tower
710 North Pleasant Street
Amherst, MA 01003-9305
United States