We show that the edges crossed by a random walk in a network form a recurrent
graph a.s. In fact, the same is true when those edges are weighted by the
number of crossings.Comment: Published at http://dx.doi.org/10.1214/009117906000000935 in the
Annals of Probability (http://www.imstat.org/aop/) by the Institute of
Mathematical Statistics (http://www.imstat.org