Removed parts from Zhu citations.

src/op/c-star/cont.tex

@@ -136,7 +136,7 @@
         \item $\norm{\Phi(x)}_B = \norm{x}_A$.
     \end{enumerate}
 \end{corollary}
-\begin{proof}[Proof, {{\cite[II.10.7]{Zhu}}}. ]
+\begin{proof}[Proof, {{\cite[10.7]{Zhu}}}. ]
     (1): Since $\Phi(G(A)) \subset G(B)$, $\sigma_B(\Phi(x)) \subset \sigma_A(x)$. If $\sigma_B(\Phi(x)) \subsetneq \sigma_A(x)$, then \hyperref[Urysohn's Lemma]{lemma:urysohn} implies that there exists $C(\sigma_A(x); \complex)$ such that $f|_{\sigma_B(\Phi(x))} = 0$ but $f \ne 0$. In which case, by (7) of the \hyperref[continuous functional calculus]{definition:continuous-functional-calculus}, $\Phi(f(x)) = f(\Phi(x)) = 0$, which contradicts the fact that $\Phi$ is injective. 
 
     (2): By \autoref{corollary:c-star-unique-norm}, $\Phi$ is isometric. 

src/op/c-star/gelfand.tex

@@ -10,7 +10,7 @@
 
     is a unital $C^*$-isomorphism. 
 \end{theorem}
-\begin{proof}[Proof, {{\cite[Theorem II.9.4]{Zhu}}}. ]
+\begin{proof}[Proof, {{\cite[Theorem 9.4]{Zhu}}}. ]
     By construction $\Gamma_A$ is a unital algebra homomorphism. 
 
     To see that $\Gamma_A$ preserves involutions, let $y \in A$ be self-adjoint. By \autoref{proposition:gelfand-transform-gymnastics} and \autoref{proposition:self-adjoint-spectrum}, $\Gamma_A(y)(\Omega(A)) = \sigma_A(y) \subset \real$, so $\Gamma_A(y) \in C(\Omega(A); \real)$. For any $x \in A$, write $x = \text{Re}(x) + i\text{Im}(x)$, where $\text{Re}(x)$ and $\text{Im}(x)$ are both self-adjoint, then

src/op/c-star/homomorphism.tex

@@ -36,4 +36,11 @@
     
 \end{proof}
 
+\begin{theorem}
+\label{theorem:continuity-of-homomorphism-c-star}
+    Let $A, B$ be unital $C^*$-algebras and $\Phi: A \to B$ be a unital *-homomorphism, then $\Phi(A)$ is closed. 
+\end{theorem}
+\begin{proof}[Proof, {{\cite[Theorem 11.1]{Zhu}}}. ]
+\end{proof}
+
 

src/op/c-star/order.tex

@@ -23,7 +23,7 @@
         \item There exists $\lambda \ge \norm{x}_A$ such that $\norm{\lambda - x}_A \le \lambda$. 
     \end{enumerate}
 \end{proposition}
-\begin{proof}[Proof, {{\cite[Lemma II.11.3]{Zhu}}}. ]
+\begin{proof}[Proof, {{\cite[Lemma 11.3]{Zhu}}}. ]
     (1) $\Leftrightarrow$ (2): \autoref{proposition:positive-spectrum}. 
 
     (2) $\Leftrightarrow$ (3): By assumption, $\sigma_A(x) \subset \real$, so \autoref{theorem:c-star-normal-spectral-radius} implies that

src/op/c-star/sa.tex

@@ -35,7 +35,7 @@
 \label{theorem:c-star-normal-spectral-radius}
     Let $A$ be a unital $C^*$-algebra and $x \in A$ be normal, then $\norm{x}_A = [x]_{sp}$. 
 \end{theorem}
-\begin{proof}[Proof, {{\cite[Theorem II.8.1]{Zhu}}}. ]
+\begin{proof}[Proof, {{\cite[Theorem 8.1]{Zhu}}}. ]
     First suppose that $x$ is self-adjoint. In this case, 
     \begin{align*}
         \normn{x^2}_A &= \normn{xx^*}_A = \norm{x}_A^2 \\

src/op/c-star/unitary.tex

@@ -42,7 +42,7 @@
 \label{proposition:unitary-spectrum}
     Let $A$ be a unital $C^*$-algebra and $x \in A$ be unitary, then $\sigma_A(x) \subset \partial B_\complex(0, 1)$. 
 \end{proposition}
-\begin{proof}[Proof, {{\cite[Proposition II.8.2]{Zhu}}}. ]
+\begin{proof}[Proof, {{\cite[Proposition 8.2]{Zhu}}}. ]
     By \autoref{lemma:unitary-unit}, $\norm{x}_A = 1$, so $\sigma_A(x) \subset \ol{B_\complex(0, 1)}$. Thus
     \[
     \bracsn{\ol{\lambda}|\lambda \in \sigma_A(x)} = \sigma_A(x^*) = \sigma_A(x^{-1}) \subset \ol{\complex \setminus B_\complex(0, 1)}