diff --git a/src/measure/vector/ac.tex b/src/measure/vector/ac.tex index cc56cf0..a669068 100644 --- a/src/measure/vector/ac.tex +++ b/src/measure/vector/ac.tex @@ -77,11 +77,18 @@ \norm{\nu(A) - \sum_{n = 1}^N \nu(A_n)}_E &= \norm{\nu\paren{A \setminus \bigsqcup_{n = 1}^N A_n}}_E \\ &= - \norm{\limv{k}\nu_k\paren{A \setminus \bigsqcup_{n = 1}^N A_n}}_E + \limv{k}\norm{\nu_k\paren{A \setminus \bigsqcup_{n = 1}^N A_n}}_E \end{align*} + Since $\seq{\nu_k}$ is uniformly absolutely continuous, + \[ + \lim_{N \to \infty}\sup_{k \in \natp}\norm{\nu_k\paren{A \setminus \bigsqcup_{n = 1}^N A_n}}_E = 0 + \] - so $\nu$ is a vector measure. Absolute continuity is equivalent to uniform continuity as a mapping $\cm_n \to E$, and uniform absolute continuity is equivalent to uniform equicontinuity as mappings $\cm \to E$. By the \hyperref[ArzelĂ -Ascoli Theorem]{theorem:arzela-ascoli}, $\nu \in UC(\cm_0; E)$, so $\nu \ll \mu$. + so $\nu$ is a vector measure. + + + Absolute continuity is equivalent to uniform continuity as a mapping $\cm_n \to E$, and uniform absolute continuity is equivalent to uniform equicontinuity as mappings $\cm \to E$. By the \hyperref[ArzelĂ -Ascoli Theorem]{theorem:arzela-ascoli}, $\nu \in UC(\cm_0; E)$, so $\nu \ll \mu$. \end{proof}