Densities and Measures of Linear Sets
B. G. A. Kelly · Canadian Mathematical Bulletin · 1973
If In, I∞ denote the intervals [0, n), [0, ∞) respectively, we propose to examine the properties of an upper and lower density (1) (1) of a set S belonging to the power set of I∞ where m*,m* denote the outer and inner (linear) Lebesgue measures.