Processing math: 100%

Monday, June 3, 2013

1.33

Recall two things. First, that m^*(E) = 0 \hspace{0.25cm} \Rightarrow E \in \mathcal{M}. Second, recall from problem 32, part a, that any measurable subset to a non-measurable set must have measure zero. Thus, since \mathcal{N}^c \cup \mathcal{N} = [0,1], it suffices to show that m(\mathcal{N}^c) = 1.

Assume to the contrary that for some \epsilon \in (0,1), \hspace{0.25cm} \mathcal{N}^c \subset U \subset [0,1], measurable, such that m(U) = 1 - \epsilon. It directly follows that ([0,1] \cap U^c) \subset \mathcal{N}. This is a contradiction, because m \big(([0,1] \cap U^c) \big) = \epsilon > 0.

Therefore, m^*(\mathcal{N}) + m^*(\mathcal{N}^c) > m(\mathcal{N} \cup \mathcal{N}^c).

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