The nonlinear and nonlocal PDE ∣vt∣p−2vt+(−Δp)sv=0,
where (−Δp)sv(x,t)=2PV∫Rn∣y∣n+sp∣v(x,t)−v(x+y,t)∣p−2(v(x,t)−v(x+y,t))dy, has the interesting feature that an associated Rayleigh quotient is
non-increasing in time along solutions. We prove the existence of a weak
solution of the corresponding initial value problem which is also unique as a
viscosity solution. Moreover, we provide H\"older estimates for viscosity
solutions and relate the asymptotic behavior of solutions to the eigenvalue
problem for the fractional p-Laplacian