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Choose any oriented link type X and closed braid
representatives X+, X- of X, where X- has minimal braid
index among all closed braid representatives of X. The main
result of this paper is a `Markov theorem without stabilization'. It
asserts that there is a complexity function and a finite set of
`templates' such that (possibly after initial complexity-reducing
modifications in the choice of X+ and X- which replace them with
closed braids X+', X-') there is a sequence of closed
braid representatives X+' =
X1→X2→…→Xr =
X-'
such that each passage Xi→Xi+1 is strictly complexity reducing
and non-increasing on braid index. The templates which define the passages
Xi→Xi+1 include 3 familiar ones, the destabilization, exchange
move and flype templates, and in addition, for each braid index m≥ 4
a finite set T(m) of new ones. The number of templates in
T(m) is a non-decreasing function of m. We give examples of
members of T(m), m≥ 4, but not a complete listing. There
are applications to contact geometry, which will be given in a separate
paper.
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