Julie Wetzer

On the friable mean-value of the Erdős-Hooley Delta function

For integer $n$ and real $u$, define $Δ(n,u):= |\{d : d \mid n,\,{\rm e}^u <d\leqslant {\rm e}^{u+1} \}|$. Then, put $ Δ(n):=\max_{u\in{\mathbb R}} Δ(n,u).$ We provide uniform upper and lower bounds for the mean-value of $Δ(n)$ over friable integers, i.e. integers free of large prime factors.