| 释义 |
null set (measure theory) A subset of a measure space having measure zero. A subset X of R is a null set if, for any ε>0, there exists intervals I1, I2, I3, …, of total length less than ε, such that X is contained in the union of the Ii. Any countable set is null, and the Cantor set is an example of an uncountable null set.
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