ABSTRACT
Essential limits have been defined in §6.4 with respect to a differential σ. In this chapter σ = dx. So essential means dx-essential, measure is Lebesgue measure M, measurable is Lebesgue measurable, almost everywhere is dx-e very where, etc. The essential properties of a function g on an interval L in R are those it shares with all functions equal a.e. to g on L. These are just the properties of g that are relevant to the differential gdx.
