From c66c3bc73d5d627ec7051e9ada6316c98ae072e0 Mon Sep 17 00:00:00 2001 From: Justin Gassner Date: Wed, 29 May 2024 14:04:59 +0200 Subject: weiter --- analytic2.tex | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'analytic2.tex') diff --git a/analytic2.tex b/analytic2.tex index e0dc68f..13b6700 100644 --- a/analytic2.tex +++ b/analytic2.tex @@ -9,7 +9,7 @@ \begin{equation*}\tag{power-series-analytic-vector} \sum_{n=0}^{\infty} \frac{A^n x}{n!} \, z^n \end{equation*} - has a nonzero radius of convergece. + has a nonzero radius of convergence. If the power series converges for all $z \in \CC$, we say that $x$ is an \emph{entire analytic vector} for $A$. \end{definition} @@ -66,13 +66,13 @@ This is a well-known consequence of the convergence behavior of power series. \end{equation*} for all $z,z'$ in the interior of $\gamma$. The family of vectors $f(w) \in X$, indexed by complex numbers $w$ on the contour $\gamma$, can be viewed as a family of bounded linear functionals $C(f(w)) : X' \to \CC$ - via the canonical embedding $C : X \to X''$ of $X$ into its bidual. For every fixed $g \in X'$ the set of values $C(f(w))(g) = g(f(w))$ is bounded, because the function $g \circ f$ is continous and the contour is compact. + via the canonical embedding $C : X \to X''$ of $X$ into its bidual. For every fixed $g \in X'$ the set of values $C(f(w))(g) = g(f(w))$ is bounded, because the function $g \circ f$ is continuous and the contour is compact. In other words, the family of functionals $C(f(w))$, $w \in \gamma$, is pointwise bounded. The Uniform Boundedness Theorem implies that there exists a constant $M > 0$ such that $\abs{g(f(w))} \le M \norm{g}$ for all $w$ on $\gamma$ and all $g \in X'$. \begin{equation*} \abs*{g \parens*{\frac{Q(z) - Q(z')}{z - z'}}} \le \frac{M}{2 \pi} \norm{g} \int_{\gamma} \frac{dw}{\abs{w-z}\abs{w-z'}\abs{w-a}} \end{equation*} - If we restict $z,z'$ to a neighbourhood $N$ of $a$ that stays away from $\gamma$, then the integral on the right hand side is + If we restrict $z,z'$ to a neighborhood $N$ of $a$ that stays away from $\gamma$, then the integral on the right hand side is bounded by a constant independent of $z$ and $z'$. Absorbing all constants into $M' > 0$ we obtain \begin{equation*} @@ -121,9 +121,9 @@ This is a well-known consequence of the convergence behavior of power series. \begin{equation*} \sum_{n=0}^{\infty} \frac{\norm{A^n x}}{n!} t^n \le M \sum_{n=0}^{\infty} \frac{t^n}{r^n} \end{equation*} - is convergent for $t \le \lambda$ by majorization. Hernce $x$ is an analytic vector for the operator $A$. + is convergent for $t \le \lambda$ by majorization. Hence $x$ is an analytic vector for the operator $A$. - Coversely, suppose that $x$ is analytic for the generator $A$ of $\sigma$. + Conversely, suppose that $x$ is analytic for the generator $A$ of $\sigma$. Then, by \cref{definition:analytic-vector-operator}, $x$ lies in the domains of all powers $A^n$, $n \in \NN$, and the power series \begin{equation*} \sum_{n=0}^{\infty} \frac{\norm{A^n x}}{n!} z^n -- cgit v1.2.3-70-g09d2