EN
For a prime p > 2, an integer a with gcd(a,p) = 1 and real 1 ≤ X,Y < p, we consider the set of points on the modular hyperbola
$𝓗_{a,p}(X,Y) = {(x,y) : xy ≡ a(mod p), 1 ≤x≤X, 1 ≤y≤Y}$.
We give asymptotic formulas for the average values
$∑_{\substack (x,y)∈ 𝓗_{a,p}(X,Y) x ≠ y*} φ(|x-y|)/|x-y|$ and $∑_{\substack (x,y)∈ 𝓗_{a,p}(X,X) x ≠ y*} φ(|x-y|)$
with the Euler function φ(k) on the differences between the components of points of $𝓗_{a,p}(X,Y)$.