diff --git a/inputs/lecture_03.tex b/inputs/lecture_03.tex index f9ae783..4517255 100644 --- a/inputs/lecture_03.tex +++ b/inputs/lecture_03.tex @@ -41,7 +41,8 @@ all condensation points are accumulation points. Fix $A \subseteq \R$ closed. We want to see that $A$ is at most countable or there is some perfect $P \subseteq A$. - Let $P \coloneqq \{x \in \R | x \text{ is a condensation point of $A$}\}$. + Let + \[P \coloneqq \{x \in \R | x \text{ is a condensation point of $A$}\}.\] Since $A $ is closed, $P \subseteq A$. \begin{claim} diff --git a/inputs/lecture_04.tex b/inputs/lecture_04.tex index 05005a2..641184f 100644 --- a/inputs/lecture_04.tex +++ b/inputs/lecture_04.tex @@ -9,7 +9,7 @@ $\ZFC$ stands for \begin{itemize} \item \textsc{Zermelo}’s axioms (1905), % crises around 19000 - \item \vocab{Fraenkel}'s axioms, + \item \textsc{Fraenkel}'s axioms, \item the axiom of choice. \end{itemize} \begin{notation} diff --git a/inputs/lecture_08.tex b/inputs/lecture_08.tex index 6685ed5..b0e5747 100644 --- a/inputs/lecture_08.tex +++ b/inputs/lecture_08.tex @@ -18,74 +18,74 @@ has the following axioms: \begin{axiom}[Extensionality] \yalabel{Axiom of Extensionality}{(Ext)}{ax:bg:ext} \[ - \forall x, y. \left( x = y \iff \left( \forall z.~(z \in x \iff z \in y \right) \right). - \] + \forall x.~\forall y.~ \left( x = y \iff \left( \forall z.~(z \in x \iff z \in y \right) \right). + \] \end{axiom} \begin{axiom}[Foundation] \yalabel{Axiom of Foundation}{(Fund)}{ax:bg:fund} \[ - \forall x .(x \neq \emptyset \implies \exists y \in x . y \cap x = \emptyset). - \] + \forall x .~(x \neq \emptyset \implies \exists y \in x .~ y \cap x = \emptyset). + \] \end{axiom} \begin{axiom}[Pairing] \yalabel{Axiom of Pairing}{(Pair)}{ax:bg:pair} \[ - \forall x \forall y \exists z . z = \{x,y\}. - \] + \forall x.~\forall y . ~\exists z .~ z = \{x,y\}. + \] \end{axiom} \begin{axiom}[Union] \yalabel{Axiom of Union}{(Union)}{ax:bg:union} \[ - \forall x \exists y .~ y = \bigcup x. - \] + \forall x .~\exists y .~ y = \bigcup x. + \] \end{axiom} \begin{axiom}[Power] \yalabel{Powerset Axiom}{(Pow)}{ax:bg:pow} \[ - \forall x \exists y .~ y = \cP(x). - \] + \forall x .~\exists y .~ y = \cP(x). + \] \end{axiom} \begin{axiom}[Infinity] \yalabel{Axiom of Infinity}{(Infinity)}{ax:bg:inf} \[ - \exists x . ~(\emptyset \in x \land \left( \forall y \in x .~y \cup \{y\} \in x \right)). - \] + \exists x .~(\emptyset \in x \land \left( \forall y \in x .~y \cup \{y\} \in x \right)). + \] \end{axiom} Together with the following axioms for classes: \begin{axiom}[Extensionality for classes] \[ - \forall X \forall Y \left( \forall x(x \in X \iff y \in X) \implies X = Y). - \] + \forall X .~\forall Y.~ \left( \forall x.~(x \in X \iff x \in Y) \implies X = Y\right). + \] \end{axiom} \begin{axiom} Every set is a class: \[ - \forall x \exists X. x = X. - \] + \forall x.~ \exists X.~ x = X. + \] \end{axiom} \begin{axiom} Every element of a class is a set: \[ - \forall X \exists Y.~(X \in Y \to \exists x.~x = X). - \] + \forall X .~\exists Y.~(X \in Y \to \exists x.~x = X). + \] \end{axiom} \begin{axiom}[Replacement] \yalabel{Axiom of Replacement}{(Rep)}{ax:bg:rep} - If $F$ is a function and inf $a $ is a set, - then $F"a$ is a set. + If $F$ is a function and $a$ is a set, + then $F\,''a$ is a set. \end{axiom} Here a \vocab[Class function]{(class) function} is a class consisting of pairs $(x,y)$, such that for every $x$ there is at most one $y$ with $(x,y) \in F$. -Furthermore $F"a \coloneqq \{y : \exists x \in a .~(x,y) \in F\}$. +Furthermore $F\,''a \coloneqq \{y : \exists x \in a .~(x,y) \in F\}$. \begin{remark} Note that we didn't need to use an axiom schema, @@ -94,10 +94,9 @@ Furthermore $F"a \coloneqq \{y : \exists x \in a .~(x,y) \in F\}$. \begin{axiom}[Comprehension] \yalabel{Axiom of Comprehension}{(Comp)}{ax:bg:comp} - \[ - \forall X_1 \ldots \forall X_k .~\exists Y ( \forall x .~x \in Y \iff \phi(x,X_1,\ldots, X_k)) - \] + \forall X_1 .~\ldots \forall X_k .~\exists Y.~ ( \forall x .~x \in Y \iff \phi(x,X_1,\ldots, X_k)) + \] where $\phi(x, X_1, \ldots, X_k)$ is a formula which contains exactly $X_1, \ldots, X_k, x$ as free variables, diff --git a/logic.sty b/logic.sty index 9b5efa9..be7a7fa 100644 --- a/logic.sty +++ b/logic.sty @@ -113,6 +113,8 @@ \DeclareSimpleMathOperator{HOD} \DeclareSimpleMathOperator{OD} \DeclareSimpleMathOperator{AC} +\newcommand{\AxC}{\yarefs{ax:c}} +\newcommand{\AxSep}{\yarefs{ax:sep}} % Separation \newcommand{\Choice}{\yarefs{ax:c}} % \DeclareSimpleMathOperator{Choice} % \DeclareSimpleMathOperator{Fund}