A2. Si $\{A_i\}_{i=1}^\infty\subset \mathcal{M}$ con $A_1\subseteq A_2\subseteq A_3\subseteq\ldots$ entonces $\displaystyle\mu(\cup_{i=1}^\infty A_i)=\lim_{j\to\infty}\mu(A_j)$.
A3. Si $\{A_i\}_{i=1}^\infty\subset\mathcal{M}$ con $A_1\supseteq A_2\supseteq A_3\supset\ldots$ con $\mu(A_1)<\infty$ entonces $\mu(\cap_{i=1}^\infty A_i)=\lim_{j\to\infty}\mu(A_j)$.