ATTRACTING EDGE AND STRONGLY EDGE REINFORCED WALKS
Vlada Limic and Pierre Tarres
The goal is to show that an edge reinforced random
walk on a graph of bounded degree, with
reinforcement {\em weight function} $W$ taken from a general class of
reciprocally summable reinforcement weight functions, traverses a
random {\em attracting} edge at all large times.
The statement of the main theorem is very close to settling
a conjecture of Sellke (1994).
An important corollary of this main result says that
if $W$ is reciprocally summable and nondecreasing,
the attracting edge exists on any graph of bounded degree, with
probability $1$.
Another corollary is the main theorem of Limic (2003) where
the class of weights was restricted to reciprocally summable powers.
The proof uses martingale and other techniques developed
by the authors in separate studies of edge and vertex reinforced
walks (Limic (2003), Tarr\`es (2004)),
and of nonconvergence properties of stochastic algorithms towards
unstable equilibrium points of the associated deterministic dynamics,
Tarr\`es (2000).