“…In fact, the theorem cannot be found there (or in other similar texts), so in [5] the second author of this paper and Z. Hao proved the theorem in detail. Of course, even after stating what "comparable to B r (x 0 )" means precisely, it is still clear that the more that is known about the collection of these D r (x 0 )'s, the more useful this theorem becomes, and since making this observation, both authors of the current paper have been studying the properties of these sets [1,2,3,4]. Of course, there is a natural definition to make: Definition 1.1 (Mean value sets).…”