Added appropriate form of Taylor's formula.
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@@ -221,7 +221,7 @@
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\end{proof}
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\begin{definition}[Complex Analytic]
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\begin{definition}[Holomorphic]
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\label{definition:complex-analytic}
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Let $E$ be a complete separated locally convex space over $\complex$, $U \subset \complex$ be open, and $f \in C(U; E)$, then the following are equivalent:
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\begin{enumerate}
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@@ -234,16 +234,16 @@
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\[
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f(z_0) = \frac{1}{2\pi i} \int_\gamma \frac{f(z)}{z - z_0}dz
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\]
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\item (\textbf{Analyticity}) For each $z_0 \in U$ and $r > 0$ such that $\ol{B(z_0, r)} \subset U$, there exists $\seq{a_n} \subset E$ such that $f$ may be expressed as a power series
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\item (\textbf{Analyticity}) For each $z_0 \in U$, there exists $r > 0$ and $\seq{a_n} \subset E$ such that for each $z \in B(z_0, r)$,
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\[
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f(z) = \sum_{n = 0}^\infty a_n(z - z_0)^n
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\]
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with radius of convergence at least $r$.
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where the radius of convergence of the series is at least $r$.
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\item (\textbf{Weak Holomorphy}) For each $\phi \in E^*$, $\phi \circ f$ satisfies the above.
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\end{enumerate}
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If the above holds, then $f$ is \textbf{complex analytic}.
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If the above holds, then $f$ is \textbf{holomorphic/complex analytic} on $U$.
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\end{definition}
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\begin{proof}
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(1) $\Leftrightarrow$ (2): \autoref{lemma:complex-analytic}.
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@@ -267,7 +267,7 @@
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Thus $[D^kf(z_0)/k!]_E \le C/r^k$ for all $k \in \natz$, and the radius of convergence of $g$ is at least $r$.
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Let $z \in B(z_0, r/2)$, $s = |z - z_0|$, and $n \in \natp$, then by \hyperref[Taylor's Formula]{theorem:taylor-lagrange} and \hyperref[Cauchy's Estimate]{corollary:cauchy-estimate},
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Let $z \in B(z_0, r/2)$, $s = |z - z_0|$, and $n \in \natp$, then by \hyperref[Taylor's Formula]{theorem:taylor-integral} and \hyperref[Cauchy's Estimate]{corollary:cauchy-estimate},
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\begin{align*}
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\braks{f(z) - \sum_{k = 0}^n \frac{1}{k!} D^kf(z_0)(z - z_0)^n}_E &\le s^{n+1} \cdot \sup_{z' \in \ol{B(z_0, s)}} [D^{n+1}f(z')]_E \\
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&\le \frac{Cs^{n+1}}{(r-s)^{n+1}}
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