We consider the generalized PageRank walk on a digraph G, with refresh probability (Formula presented.) and resampling distribution (Formula presented.). We analyze convergence to stationarity when G is a large sparse random digraph with given degree sequences, in the limit of vanishing (Formula presented.). We identify three scenarios: when (Formula presented.) is much smaller than the inverse of the mixing time of G the relaxation to equilibrium is dominated by the simple random walk and displays a cutoff behavior; when (Formula presented.) is much larger than the inverse of the mixing time of G on the contrary one has pure exponential decay with rate (Formula presented.); when (Formula presented.) is comparable to the inverse of the mixing time of G there is a mixed behavior interpolating between cutoff and exponential decay. This trichotomy is shown to hold uniformly in the starting point and uniformly in the resampling distribution (Formula presented.).
Caputo, P., Quattropani, M. (2021). Mixing time of PageRank surfers on sparse random digraphs. RANDOM STRUCTURES & ALGORITHMS, 59(3), 376-406 [10.1002/rsa.21009].
Mixing time of PageRank surfers on sparse random digraphs
Caputo P.;Quattropani M.
2021-01-01
Abstract
We consider the generalized PageRank walk on a digraph G, with refresh probability (Formula presented.) and resampling distribution (Formula presented.). We analyze convergence to stationarity when G is a large sparse random digraph with given degree sequences, in the limit of vanishing (Formula presented.). We identify three scenarios: when (Formula presented.) is much smaller than the inverse of the mixing time of G the relaxation to equilibrium is dominated by the simple random walk and displays a cutoff behavior; when (Formula presented.) is much larger than the inverse of the mixing time of G on the contrary one has pure exponential decay with rate (Formula presented.); when (Formula presented.) is comparable to the inverse of the mixing time of G there is a mixed behavior interpolating between cutoff and exponential decay. This trichotomy is shown to hold uniformly in the starting point and uniformly in the resampling distribution (Formula presented.).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.