In this paper, we use methods from spectral graph theory to obtain some results on the sum–product problem over finite valuation rings
R of order
qr which generalize recent results given by Hegyvári and Hennecart (2013). More precisely, we prove that, for related pairs of two-variable functions
f(x,y) and
g(x,y), if
A and
B are two sets in
R∗ with
|A|=|B|=qα, then
for some
575460264c0956" title="Click to view the MathML source">Δ(α)>0.