简介:TheauthorpresentssomestraightforwardproofsfortwocomparisontheoremsforGreenfunctionsofMarkovchains,whichslightlyimprovethepreviousresultsbyVaropoulos,DurrettandYanandChen.ArecentresultbyRogersandWilliamsaboutinstantaneousMarkovchainsisalsoimprovedbyusingthesameidea.