diff --git a/src/measure/lcg/lcg.tex b/src/measure/lcg/lcg.tex index 9f32a7c..19a83a6 100644 --- a/src/measure/lcg/lcg.tex +++ b/src/measure/lcg/lcg.tex @@ -3,7 +3,7 @@ \begin{definition}[Locally Compact Group] \label{definition:lcg} - Let $G$ be a topological group, then $G$ is \textbf{locally compact} if $G$ is a LCH space. + Let $G$ be a topological group, then $G$ is \textbf{locally compact} if $G$ is an LCH space. \end{definition} \begin{proposition} diff --git a/src/measure/measure/regular.tex b/src/measure/measure/regular.tex index fc41431..9c98355 100644 --- a/src/measure/measure/regular.tex +++ b/src/measure/measure/regular.tex @@ -28,7 +28,7 @@ \label{theorem:sigma-compact-regular-measure} Let $X$ be a topological space and $\mu: \cb_X \to [0, \infty]$ be a Borel measure. If: \begin{enumerate} - \item[(a)] $X$ is a LCH space. + \item[(a)] $X$ is an LCH space. \item[(b)] Every open set of $X$ is $\sigma$-compact. \item[(c)] For any $K \subset X$ compact, $\mu(K) < \infty$. \end{enumerate} diff --git a/src/measure/measure/scaffold.tex b/src/measure/measure/scaffold.tex index 4fb139a..71e2d1b 100644 --- a/src/measure/measure/scaffold.tex +++ b/src/measure/measure/scaffold.tex @@ -16,7 +16,7 @@ \end{definition} \begin{example} - Let $X$ be a LCH space, $\mu$ be a semifinite Radon measure, and $\mathcal{K}$ be the collection of compact subsets of $X$, then $\mathcal{K}$ is a scaffold for $\mu$. + Let $X$ be an LCH space, $\mu$ be a semifinite Radon measure, and $\mathcal{K}$ be the collection of compact subsets of $X$, then $\mathcal{K}$ is a scaffold for $\mu$. \end{example} % Omitted diff --git a/src/measure/radon/c0.tex b/src/measure/radon/c0.tex index 7d2a06b..42cf621 100644 --- a/src/measure/radon/c0.tex +++ b/src/measure/radon/c0.tex @@ -20,14 +20,14 @@ \begin{definition}[Radon Measure] \label{definition:radon-measure-extended} - Let $X$ be a LCH space and $\mu$ be a Borel signed/vector measure on $X$, then $\mu$ is \textbf{Radon} if $|\mu|$ is Radon. + Let $X$ be an LCH space and $\mu$ be a Borel signed/vector measure on $X$, then $\mu$ is \textbf{Radon} if $|\mu|$ is Radon. \end{definition} \begin{definition}[Space of Finite Radon Measures] \label{definition:space-radon-measures} - Let $X$ be a LCH space and $E$ be a normed vector space over $K \in \RC$, then $M_R(X; E)$ is the \textbf{space of finite Radon measures} on $X$, which forms a vector space over $K$. + Let $X$ be an LCH space and $E$ be a normed vector space over $K \in \RC$, then $M_R(X; E)$ is the \textbf{space of finite Radon measures} on $X$, which forms a vector space over $K$. \end{definition} \begin{proof} Let $\mu, \nu \in M_R(X; E)$, then for any $A \in \cb_X$, $|\mu + \nu|(A) \le |\mu|(A) + |\nu|(A)$. Let $\eps > 0$, then by outer regularity and \autoref{proposition:radon-measurable-description}, there exists $K \subset A$ compact and $U \in \cn^o(A)$ such that $(|\mu| + |\nu|)(A \setminus K), (|\mu| + |\nu|)(U \setminus A) < \eps$. Therefore $|\mu + \nu|$ is regular on all Borel sets, and hence Radon. @@ -132,7 +132,7 @@ then $T$ is maps $C_0(X; E)$ continuously into a subspace of $C_0(X \times B; K)$. - Let $I \in C_0(X; E)^*$, then by the \hyperref[Hahn-Banach theorem]{theorem:hahn-banach}, there exists $\ol{I} \in C_0(X \times B; K)^*$ such that $\ol I \circ T = I$. By \hyperref[Alaoglu's Theorem]{theorem:alaoglu}, $B$ is a compact Hausdorff space. Therefore $X \times B$ is a LCH space by \autoref{proposition:lch-product}. By the \hyperref[Riesz Representation Theorem]{theorem:riesz-radon-c0}, there exists $\mu \in M_R(X \times B; K)$ such that for any $f \in C_0(X \times B; K)$, + Let $I \in C_0(X; E)^*$, then by the \hyperref[Hahn-Banach theorem]{theorem:hahn-banach}, there exists $\ol{I} \in C_0(X \times B; K)^*$ such that $\ol I \circ T = I$. By \hyperref[Alaoglu's Theorem]{theorem:alaoglu}, $B$ is a compact Hausdorff space. Therefore $X \times B$ is an LCH space by \autoref{proposition:lch-product}. By the \hyperref[Riesz Representation Theorem]{theorem:riesz-radon-c0}, there exists $\mu \in M_R(X \times B; K)$ such that for any $f \in C_0(X \times B; K)$, \[ \dpn{f, \ol I}{C_0(X \times B; K)} = \int_{X \times B} f d\mu \] diff --git a/src/measure/radon/radon.tex b/src/measure/radon/radon.tex index c85aed2..dc8dd9c 100644 --- a/src/measure/radon/radon.tex +++ b/src/measure/radon/radon.tex @@ -3,7 +3,7 @@ \begin{definition}[Radon Measure] \label{definition:radon-measure} - Let $X$ be a LCH space and $\mu: \cb_X \to [0, \infty]$ be a Borel measure, then $\mu$ is a \textbf{Radon measure} if: + Let $X$ be an LCH space and $\mu: \cb_X \to [0, \infty]$ be a Borel measure, then $\mu$ is a \textbf{Radon measure} if: \begin{enumerate} \item[(R1)] For any $K \subset X$ compact, $\mu(K) < \infty$. \item[(R2)] $\mu$ is outer regular on all Borel sets. @@ -13,7 +13,7 @@ \begin{proposition} \label{proposition:radon-measure-cc} - Let $X$ be a LCH space and $\mu: \cb_X \to [0, \infty]$ be a Radon measure, then + Let $X$ be an LCH space and $\mu: \cb_X \to [0, \infty]$ be a Radon measure, then \begin{enumerate} \item For any $U \subset X$ open, \[ @@ -53,7 +53,7 @@ \begin{proposition} \label{proposition:radon-regular-sigma-finite} - Let $X$ be a LCH space and $\mu: \cb_X \to [0, \infty]$ be a Radon measure, then + Let $X$ be an LCH space and $\mu: \cb_X \to [0, \infty]$ be a Radon measure, then \begin{enumerate} \item $\mu$ is inner regular on all its $\sigma$-finite sets. \item If $X$ is $\sigma$-compact or $\mu$ is $\sigma$-finite, then $\mu$ is regular. @@ -87,7 +87,7 @@ \begin{proposition} \label{proposition:radon-measurable-description} - Let $X$ be a LCH space, $\mu: \cb_X \to [0, \infty]$ be a $\sigma$-finite Radon measure, and $E \in \cb_X$, then + Let $X$ be an LCH space, $\mu: \cb_X \to [0, \infty]$ be a $\sigma$-finite Radon measure, and $E \in \cb_X$, then \begin{enumerate} \item For every $\eps > 0$, there exists $U \in \cn^o(E)$ and $F \subset E$ closed such that $\mu(U \setminus F) < \eps$. \item There exists a $F_\sigma$ set $A$ and a $G_\delta$ set $B$ such that $A \subset E \subset B$ and $\mu(B \setminus A) = 0$. @@ -111,7 +111,7 @@ \begin{proposition} \label{proposition:finite-compact-regular} - Let $X$ be a LCH space and $\mu: \cb_X \to [0, \infty]$ be a Borel measure such that: + Let $X$ be an LCH space and $\mu: \cb_X \to [0, \infty]$ be a Borel measure such that: \begin{enumerate} \item[(a)] For any $U \subset X$ open, $U$ is $\sigma$-compact. \item[(b)] For any $K \subset X$ compact, $\mu(K) < \infty$. @@ -151,7 +151,7 @@ \begin{lemma} \label{lemma:radon-compact-project} - Let $X$ be a LCH space, $Y$ be a compact Hausdorff space, $\mu$ be a finite Radon measure on $X \times Y$, and $\nu$ be a measure on $X$. If for each $A \in \cb_X$, $\nu(A) \le \mu(A \times Y)$, then $\nu$ is also a Radon measure. + Let $X$ be an LCH space, $Y$ be a compact Hausdorff space, $\mu$ be a finite Radon measure on $X \times Y$, and $\nu$ be a measure on $X$. If for each $A \in \cb_X$, $\nu(A) \le \mu(A \times Y)$, then $\nu$ is also a Radon measure. \end{lemma} \begin{proof} Let $A \in \cb_X$ and $\eps > 0$. By outer regularity of $\mu$, there exists $U \in \cn_{X \times Y}(A \times Y)$ such that $\mu(U \setminus (A \times Y)) < \eps$. By the \hyperref[Tube Lemma]{lemma:tube-lemma}, there exists $V \in \cn_X(A)$ such that $V \times Y \subset U$. In which case, @@ -172,7 +172,7 @@ \begin{proposition} \label{proposition:radon-cc-dense} - Let $X$ be a LCH space, $\mu: \cb_X \to [0, \infty]$ be a Radon measure, $E$ be a normed vector space, and $p \in [1, \infty)$, then $C_c(X; E)$ is dense in $L^p(X; E)$. + Let $X$ be an LCH space, $\mu: \cb_X \to [0, \infty]$ be a Radon measure, $E$ be a normed vector space, and $p \in [1, \infty)$, then $C_c(X; E)$ is dense in $L^p(X; E)$. \end{proposition} \begin{proof} By \autoref{proposition:lp-simple-dense}, $\Sigma(X, \cm; E) \cap L^p(X; E)$ is dense in $L^p(X; E)$. Using linearity, it is sufficient to approximate indicator functions of Borel sets with finite measure. @@ -187,7 +187,7 @@ \begin{theorem}[Lusin] \label{theorem:lusin} - Let $X$ be a LCH space, $\mu$ be a Radon measure on $X$, $E$ be a normed vector space, and $f: X \to E$ be a measurable function with $\mu\bracs{f \ne 0} < \infty$, then for any $\eps > 0$, + Let $X$ be an LCH space, $\mu$ be a Radon measure on $X$, $E$ be a normed vector space, and $f: X \to E$ be a measurable function with $\mu\bracs{f \ne 0} < \infty$, then for any $\eps > 0$, \begin{enumerate} \item There exists $A \subset \bracs{f \ne 0}$ such that $f|_A$ is continuous and $\mu(\bracs{f \ne 0} \setminus A) < \eps$ \item If $E = \complex$, then there exists $\phi \in C_c(X; E)$ such that $\mu\bracs{f \ne \phi} < \eps$. @@ -228,7 +228,7 @@ \begin{proposition}[Monotone Convergence Theorem (LSC)] \label{proposition:mct-radon} - Let $X$ be a LCH space, $\net{f}$ and $f: X \to [0, \infty]$ be non-negative lower semicontinuous functions such that $f_\alpha \upto f$, then for any Radon measure $\mu$ on $X$, + Let $X$ be an LCH space, $\net{f}$ and $f: X \to [0, \infty]$ be non-negative lower semicontinuous functions such that $f_\alpha \upto f$, then for any Radon measure $\mu$ on $X$, \[ \int f d\mu = \sup_{\alpha \in A}\int f_\alpha d\mu \] diff --git a/src/measure/radon/riesz.tex b/src/measure/radon/riesz.tex index 7ba791e..f2e5b82 100644 --- a/src/measure/radon/riesz.tex +++ b/src/measure/radon/riesz.tex @@ -8,7 +8,7 @@ \begin{proposition} \label{proposition:positive-linear-functional-cc-property} - Let $X$ be a LCH space and $I \in \hom(C_c(X; \real); \real)$ be a positive linear functional, then + Let $X$ be an LCH space and $I \in \hom(C_c(X; \real); \real)$ be a positive linear functional, then \begin{enumerate} \item For any $f, g \in C_c(X; \real)$ with $f \le g$, $\dpb{f, I}{C_c(X; \real)} \le \dpb{g, I}{C_c(X; \real)}$. \item For any $K \subset X$ compact, there exists $C_K \ge 0$ such that for all $f \in C_c(X; \real)$ with $\supp{f} \subset K$, $|{\dpb{f, I}{C_c(X; \real)}}| \le \norm{f}_u$. @@ -28,7 +28,7 @@ \begin{theorem}[Riesz Representation Theorem] \label{theorem:riesz-radon} - Let $(X, \topo)$ be a LCH space and $I \in \hom(C_c(X; \real); \real)$ be a positive linear functional, then there exists a Borel measure $\mu: \cb_X \to [0, \infty]$ such that: + Let $(X, \topo)$ be an LCH space and $I \in \hom(C_c(X; \real); \real)$ be a positive linear functional, then there exists a Borel measure $\mu: \cb_X \to [0, \infty]$ such that: \begin{enumerate} \item For any $U \subset X$ open, $\mu(U) = \sup_{f \prec U}\dpb{f, I}{C_c(X; \real)}$. \item For any $K \subset X$ compact, $\mu(K) = \inf_{f \in C_c(X; [0, 1]), f \ge \one_K}\dpb{f, I}{C_c(X; \real)}$. diff --git a/src/measure/vector/fin.tex b/src/measure/vector/fin.tex index f6c1176..faf5086 100644 --- a/src/measure/vector/fin.tex +++ b/src/measure/vector/fin.tex @@ -119,7 +119,7 @@ Despite not covering the full dual space, the bounded Borel functions still form \begin{proposition} \label{proposition:space-of-measures-extreme-points} - Let $X$ be a LCH space and $\cm \subset \overline{B_{M_R(X; \complex)}(0, 1)}$ be a compact convex set such that: + Let $X$ be an LCH space and $\cm \subset \overline{B_{M_R(X; \complex)}(0, 1)}$ be a compact convex set such that: \begin{enumerate}[label=(\alph*)] \item For each $\mu \in \cm$ and $A, B \in \cb_X$, let $\mu_A(B) = \mu(A \cap B)$, then $\mu_A \in \cm$. \item For each $\mu \in \cm \setminus \bracs{0}$ and $t \in [0, 1/\norm{\mu}_{\text{var}}]$, $t\mu \in \cm$. diff --git a/src/op/banach/multiplicative.tex b/src/op/banach/multiplicative.tex index e3c9090..45c1fcc 100644 --- a/src/op/banach/multiplicative.tex +++ b/src/op/banach/multiplicative.tex @@ -37,7 +37,7 @@ Let $A$ be a Banach algebra, then $\Omega(A)$ is the \textbf{space of multiplicative linear functionals}, and with respect to the weak-* topology, \begin{enumerate} \item If $A$ is unital, then $\Omega(A)$ is a compact Hausdorff space. - \item $\Omega(A) \cup \bracs{0}$ is a compact Hausdorff space, and $\Omega(A)$ is a LCH space. + \item $\Omega(A) \cup \bracs{0}$ is a compact Hausdorff space, and $\Omega(A)$ is an LCH space. \end{enumerate} \end{definition} \begin{proof} diff --git a/src/op/example/c0.tex b/src/op/example/c0.tex index e49f43c..1bae76e 100644 --- a/src/op/example/c0.tex +++ b/src/op/example/c0.tex @@ -3,12 +3,12 @@ \begin{definition}[$C_0(X)$] \label{definition:vanishing-infinity-algebra} - Let $X$ be a LCH space, then $C_0(X; \complex)$ equipped with pointwise operations and the uniform norm is a $C^*$-algebra. + Let $X$ be an LCH space, then $C_0(X; \complex)$ equipped with pointwise operations and the uniform norm is a $C^*$-algebra. \end{definition} \begin{theorem} \label{theorem:vanishing-infinity-multiplicative-functional} - Let $X$ be a LCH space, then the mapping + Let $X$ be an LCH space, then the mapping \[ E: X \to \Omega(C_0(X)) \quad E(x)(f) = f(x) \] diff --git a/src/topology/main/c0.tex b/src/topology/main/c0.tex index e888edc..2d412f4 100644 --- a/src/topology/main/c0.tex +++ b/src/topology/main/c0.tex @@ -17,7 +17,7 @@ For details regarding the complex-valued cased, in particular its properties as \begin{enumerate} \item $C_0(X; E) \subset BC(X; E)$. \item $C_0(X; E)$ is a closed subspace of $BC(X; E)$ with respect to the uniform topology. In particular, if $E$ is complete, then so is $C_0(X; E)$. - \item If $X$ is a LCH space, then $C_c(X; E)$ is a dense subspace of $C_0(X; E)$ with respect to the uniform topology. + \item If $X$ is an LCH space, then $C_c(X; E)$ is a dense subspace of $C_0(X; E)$ with respect to the uniform topology. \end{enumerate} \end{proposition} \begin{proof} @@ -44,7 +44,7 @@ For details regarding the complex-valued cased, in particular its properties as \begin{proposition} \label{proposition:c0-tensor} - Let $X$ be a LCH space and $E$ be a locally convex space over $K \in \RC$. Identify $C_0(X; K) \otimes E$ as a subspace of $C_0(X; E)$ under the natural map + Let $X$ be an LCH space and $E$ be a locally convex space over $K \in \RC$. Identify $C_0(X; K) \otimes E$ as a subspace of $C_0(X; E)$ under the natural map \[ C_0(X; K) \otimes E \to C_0(X; E) \quad \sum_{j = 1}^n \phi_j \otimes x_j \mapsto \sum_{j = 1}^n x_j \cdot \phi_j \] diff --git a/src/topology/main/compactify.tex b/src/topology/main/compactify.tex index b2078fc..bbacf05 100644 --- a/src/topology/main/compactify.tex +++ b/src/topology/main/compactify.tex @@ -73,7 +73,7 @@ \begin{lemma} \label{lemma:lch-compactification-open} - Let $X$ be a LCH space and $(Y, \varphi)$ be a compactification of $X$, then $\varphi(X) \subset Y$ is open. + Let $X$ be an LCH space and $(Y, \varphi)$ be a compactification of $X$, then $\varphi(X) \subset Y$ is open. \end{lemma} \begin{proof} For each $x \in X$, let $U \in \cn_X(x)$ be a compact neighbourhood. Since $Y$ is a compact Hausdorff space, $\varphi(U)$ is closed by \autoref{proposition:compact-closed}. As $\varphi \in C(X; Y)$ is an embedding, there exists $V \in \cn_Y(\varphi(x))$ such that $\varphi(U) = \varphi(X) \cap V$. Given that $\varphi(X)$ is dense in $Y$, $\varphi(U) = \ol{\varphi(X) \cap V} \supset V$. Therefore $\varphi(U) \in \cn_{Y}(\varphi(x))$, and $\varphi(X)$ is open in $Y$. @@ -83,7 +83,7 @@ \begin{definition}[One-Point Compactification] \label{definition:alexandroff-compactification} - Let $(X, \mathcal{T})$ be a LCH space, then there exists a pair $(X^*, \iota)$ such that: + Let $(X, \mathcal{T})$ be an LCH space, then there exists a pair $(X^*, \iota)$ such that: \begin{enumerate} \item $(X^*, \iota)$ is a compactification of $X$. \item[(U)] For any pair $(Y, \varphi)$ satisfying (1), there exists a unique $\varphi^* \in C(Y; X^*)$ such that the following diagram commutes: diff --git a/src/topology/main/lch.tex b/src/topology/main/lch.tex index 1f8f19c..b5d8d99 100644 --- a/src/topology/main/lch.tex +++ b/src/topology/main/lch.tex @@ -20,7 +20,7 @@ \begin{lemma} \label{lemma:lch-compact-neighbour} - Let $X$ be a LCH space, $K \subset X$ be compact, and $U \in \cn(K)$, then there exits $V \in \cn^o(K)$ relatively compact such that $K \subset V \subset \ol{V} \subset U$. + Let $X$ be an LCH space, $K \subset X$ be compact, and $U \in \cn(K)$, then there exits $V \in \cn^o(K)$ relatively compact such that $K \subset V \subset \ol{V} \subset U$. \end{lemma} \begin{proof} For each $x \in K$, there exists $V_x \in \cn^o(x)$ be relatively compact such that $x \in V_x \subset \overline{V_x} \subset U$ by (3) of \autoref{definition:lch}. Since $K$ is compact, there exists $\seqf{x_j} \subset K$ such that @@ -38,7 +38,7 @@ \begin{lemma}[Urysohn's Lemma (LCH)] \label{lemma:lch-urysohn} - Let $X$ be a LCH space, $K \subset X$ be compact, and $U \in \cn(K)$, then there exists $F \in C_c(X; [0, 1])$ such that $\supp{F} \subset U$. + Let $X$ be an LCH space, $K \subset X$ be compact, and $U \in \cn(K)$, then there exists $F \in C_c(X; [0, 1])$ such that $\supp{F} \subset U$. \end{lemma} \begin{proof}[Proof, {{\cite[Lemma 4.32]{Folland}}}. ] By \autoref{lemma:lch-compact-neighbour}, there exists $V, W \in \cn^o(K)$ relatively compact such that @@ -61,7 +61,7 @@ \begin{theorem}[Tietze Extension Theorem (LCH)] \label{theorem:lch-tietze} - Let $X$ be a LCH space, $K \subset X$ be compact, $U \in \cn^o(K)$, and $f \in C(K; \real)$, then there exists $F \in C_c(U; \real)$ such that $F|_K = f$. + Let $X$ be an LCH space, $K \subset X$ be compact, $U \in \cn^o(K)$, and $f \in C(K; \real)$, then there exists $F \in C_c(U; \real)$ such that $F|_K = f$. \end{theorem} \begin{proof} By \autoref{lemma:lch-compact-neighbour}, there exists $V, W \in \cn^o(K)$ relatively compact such that $K \subset V \subset \ol{V} \subset U$. As $\ol{W}$ is compact, it is normal by \autoref{proposition:compact-hausdorff-normal}. Since $X$ is Hausdorff, $K \subset \ol{W}$ is closed by \autoref{proposition:compact-closed}. @@ -79,7 +79,7 @@ \begin{proposition} \label{proposition:lch-compactly-generated} - Let $X$ be a LCH space, then: + Let $X$ be an LCH space, then: \begin{enumerate} \item $X$ is compactly generated. \item For any uniform space $Y$, $C(X; Y) \subset Y^X$ is closed with respect to the compact-open topology. @@ -94,7 +94,7 @@ \begin{proposition} \label{proposition:lch-product} - Let $\seqi{X}$ be a family of LCH spaces. If $X_i$ is compact for all but finitely many $i \in I$, then $X = \prod_{i \in I}X_i$ is a LCH space. + Let $\seqi{X}$ be a family of LCH spaces. If $X_i$ is compact for all but finitely many $i \in I$, then $X = \prod_{i \in I}X_i$ is an LCH space. \end{proposition} \begin{proof} By \autoref{proposition:product-hausdorff}, $\prod_{i \in I}X_i$ is Hausdorff. Let $x \in \prod_{i \in I}X_i$ and $i \in I$. If $X_i$ is not compact, let $U_i \in \cn_{X_i}(\pi_i(x))$ be compact. Otherwise, let $U_i = X_i$. Let $U = \prod_{i \in I}U_i$, then since $U_i \ne X_i$ for only finitely many $i \in I$, $U \in \cn_X(x)$. By \hyperref[Tychonoff's Theorem]{theorem:tychonoff}, $U$ is compact. Therefore $X$ is locally compact. @@ -108,7 +108,7 @@ \begin{proposition} \label{proposition:lch-sigma-compact} - Let $X$ be a LCH space, then the following are equivalent: + Let $X$ be an LCH space, then the following are equivalent: \begin{enumerate} \item $X$ is $\sigma$-compact. \item There exists an exhaustion of $X$ by compact sets. @@ -134,7 +134,7 @@ \begin{proposition} \label{proposition:lch-partition-of-unity} - Let $X$ be a LCH space, $K \subset X$ be compact, and $\seqi{U}$ be an open cover of $K$, then there exists a $C_c$ partition of unity on $K$ subordinate to $\seqi{U}$. + Let $X$ be an LCH space, $K \subset X$ be compact, and $\seqi{U}$ be an open cover of $K$, then there exists a $C_c$ partition of unity on $K$ subordinate to $\seqi{U}$. \end{proposition} \begin{proof}[Proof, {{\cite[Proposition 4.41]{Folland}}}. ] Since $K$ is compact, assume without loss of generality that $\seqi{U} = \seqf{U_j}$. @@ -160,7 +160,7 @@ \begin{lemma} \label{lemma:lch-locally-finite-relatively-compact-refine} - Let $X$ be a LCH space and $\ce \subset 2^X$ be a locally finite relatively compact open cover of $X$, then there exists locally finite relatively compact open covers $\bracs{F_E}_{E \in \ce}, \bracs{G_E}_{E \in \ce} \subset 2^X$ such that for each $E \in \ce$, $G_E \subset \ol{G_E} \subset E \subset \ol{E} \subset F_E$. + Let $X$ be an LCH space and $\ce \subset 2^X$ be a locally finite relatively compact open cover of $X$, then there exists locally finite relatively compact open covers $\bracs{F_E}_{E \in \ce}, \bracs{G_E}_{E \in \ce} \subset 2^X$ such that for each $E \in \ce$, $G_E \subset \ol{G_E} \subset E \subset \ol{E} \subset F_E$. \end{lemma} \begin{proof} $(\bracs{F_E}_{E \in \ce})$: For each $E \in \ce$, $\bracsn{F \in \ce|F \cap \ol E \ne \emptyset}$ is finite by \autoref{lemma:locally-finite-compact}. Let @@ -210,7 +210,7 @@ \begin{theorem} \label{theorem:lch-paracompact} - Let $X$ be a LCH space, then the following are equivalent: + Let $X$ be an LCH space, then the following are equivalent: \begin{enumerate} \item $X$ is paracompact. \item There exists a locally finite relatively compact open cover $\cf$ of $X$. diff --git a/src/topology/main/semicontinuity.tex b/src/topology/main/semicontinuity.tex index 3c4c5a7..384dc8d 100644 --- a/src/topology/main/semicontinuity.tex +++ b/src/topology/main/semicontinuity.tex @@ -64,7 +64,7 @@ \begin{proposition} \label{proposition:semicontinuous-lch} - Let $X$ be a LCH space and $f: X \to [0, \infty]$ be lower semicontinuous, then + Let $X$ be an LCH space and $f: X \to [0, \infty]$ be lower semicontinuous, then \[ f = \sup_{\substack{\phi \in C_c(X) \\ 0 \le \phi \le f}}\phi \] diff --git a/src/topology/uniform/equicontinuous.tex b/src/topology/uniform/equicontinuous.tex index 283fa2b..bd9cd89 100644 --- a/src/topology/uniform/equicontinuous.tex +++ b/src/topology/uniform/equicontinuous.tex @@ -57,7 +57,7 @@ \item $\cf$ is a relatively compact subset of $C(X; Y)$ with respect to the uniform structure of compact convergence. \end{enumerate} - Conversely, if $X$ is a LCH space, then (C3) implies (E1) + (E2). + Conversely, if $X$ is an LCH space, then (C3) implies (E1) + (E2). \end{theorem} \begin{proof} (E1) $\Rightarrow$ (C1): It is sufficient to show that (ii) is finer than (iii). @@ -80,7 +80,7 @@ (E1) + (E2) $\Rightarrow$ (C3): Using (C2), assume without loss of generality that $\cf$ is closed in $Y^X$ with respect to the product topology. In which case, $\cf$ is a closed subset of $\prod_{x \in X}\ol{\cf(x)}$ with respect to the product topology. By \hyperref[Tychonoff's Theorem]{theorem:tychonoff} and \autoref{proposition:compact-extensions}, $\cf$ is compact in the product topology. By (C1), $\cf$ is also compact in the compact uniform topology. - (C3) $\Rightarrow$ (E1): Assume that $X$ is a LCH space. Let $x \in X$ and $U \in \fU$ be symmetric, then there exists a compact neighbourhood $V \in \cn_X(x)$. Since $\cf$ is totally bounded, there exists $\seqf{f_j} \subset \cf$ such that for each $g \in \cf$, there exists $1 \le j \le n$ such that $(f_j \times g)(V) \subset U$. For each $1 \le j \le n$, $f_j \in C(X; Y)$, so there exists $V_j \in \cn_X(x)$ with $V_j \subset V$ such that for any $y \in V_j$, $(f_j(x), f_j(y)) \in U$. Let $W = \bigcap_{j = 1}^n V_j$, then for any $g \in \cf$ with $(f_j \times g)(V) \subset U$ and $y \in W$, + (C3) $\Rightarrow$ (E1): Assume that $X$ is an LCH space. Let $x \in X$ and $U \in \fU$ be symmetric, then there exists a compact neighbourhood $V \in \cn_X(x)$. Since $\cf$ is totally bounded, there exists $\seqf{f_j} \subset \cf$ such that for each $g \in \cf$, there exists $1 \le j \le n$ such that $(f_j \times g)(V) \subset U$. For each $1 \le j \le n$, $f_j \in C(X; Y)$, so there exists $V_j \in \cn_X(x)$ with $V_j \subset V$ such that for any $y \in V_j$, $(f_j(x), f_j(y)) \in U$. Let $W = \bigcap_{j = 1}^n V_j$, then for any $g \in \cf$ with $(f_j \times g)(V) \subset U$ and $y \in W$, \[ (g(x), f_j(x)), (f_j(x), f_j(y)), (f_j(y), g(y)) \in U \circ U \circ U \]