relative variancerelative velocityrelativelyrelatively compact setrelatively openrelatively open setrelatively primerelatively prime numbersrelativisticrelativistic effectrelativistic mass equationrelativityrelativizationrelativization of a topologyrelavantreliabilityreliability coefficientreliablereliefrelleasedrelocatereluctanceremainremain at restremainderremainder formularemainder functionremainder least absoluteremainder of a seriesremainder of an infinite seriesremainder principalremainder termremainder theoremremaining durationremains unchangedremarkremarks forremotenessremovableremovable discontinuityremovable plate moldremovable singular pointremovable singularityremovalremoval of a term of an equationremoverenderringrenewalrenewal functionrenewal theorem