简介:Foranyx∈(0,1](exceptatmostcountablymanypoints),thereexistsauniquesequence{dn(x)}n≥1ofintegers,calledthedigitsequenceofx,suchthat■.ThedexterinfiniteseriesexpansioniscalledtheL¨urothexpansionofx.ThispaperisconcernedwiththesizeofthesetofpointsxwhosedigitsequenceinitsL¨urothexpansionisstrictlyincreasingandcontainsarbitrarilylongarithmeticprogressionswitharbitrarycommondifference.Moreprecisely,wedeterminetheHausdorffdimensionoftheaboveset.