In this paper, we use methods from spectral graph
theory to obtain some results on
the sum–product problem over finite valuation rings
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si1.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=f5b95ec2bf3bc99124783bdd794b41ea" title="Click to view the MathML source">Rclass="mathContainer hidden">class="mathCode"> of order
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si2.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=7cfe0f840f38ea17d199b860a602b5af" title="Click to view the MathML source">qrclass="mathContainer hidden">class="mathCode"> which generalize recent results given by Hegyvári and
Hennecart (2013). More precisely, we prove that, for related pairs of two-variable functions
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si3.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=892d3b882569a7461ed46ae16d28d269" title="Click to view the MathML source">f(x,y)class="mathContainer hidden">class="mathCode"> and
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si4.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=431d1407dfe554e0e1f51bd858e738ea" title="Click to view the MathML source">g(x,y)class="mathContainer hidden">class="mathCode">, if
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si5.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=4250ed32078001a74daf4e5e07e674d3" title="Click to view the MathML source">Aclass="mathContainer hidden">class="mathCode"> and
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si6.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=8d077ea61114667f2672380f808f5e52" title="Click to view the MathML source">Bclass="mathContainer hidden">class="mathCode"> are two sets in
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si7.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=4c989ef6bfb24c48db4a96699bf01f72" title="Click to view the MathML source">R∗class="mathContainer hidden">class="mathCode"> with
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si8.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=f09c3daae10a0ce8821c9f42d86800f5" title="Click to view the MathML source">|A|=|B|=qαclass="mathContainer hidden">class="mathCode">,
then
class="formula" id="fd000005">
class="mathml">
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si9.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=a6057381ae00e05828007059ade3bf80" title="Click to view the MathML source">max{|f(A,B)|,|g(A,B)|}≫|A|1+Δ(α),class="mathContainer hidden">class="mathCode">![]()
class="temp" src="/sd/blank.gif">
for some
class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0195669816300865&_mathId=si10.gif&_user=111111111&_pii=S0195669816300865&_rdoc=1&_issn=01956698&md5=502a6f0ca7c4635d88575460264c0956" title="Click to view the MathML source">Δ(α)>0class="mathContainer hidden">class="mathCode">.