This commit is contained in:
parent
acb56df1c2
commit
e59e97ca03
2 changed files with 5 additions and 3 deletions
|
@ -59,12 +59,11 @@
|
||||||
Take $A \in \Sigma^1_1(X) \setminus \cB(X)$%
|
Take $A \in \Sigma^1_1(X) \setminus \cB(X)$%
|
||||||
\footnote{e.g.~\yaref{thm:universals11}}
|
\footnote{e.g.~\yaref{thm:universals11}}
|
||||||
and $f\colon X \to Y$ Borel.
|
and $f\colon X \to Y$ Borel.
|
||||||
But then we get that $f^{-1}(B)$ is Borel $\lightnig$.
|
But then we get that $f^{-1}(B)$ is Borel $\lightning$.
|
||||||
}{.}
|
}{.}
|
||||||
\end{itemize}
|
\end{itemize}
|
||||||
\end{observe}
|
\end{observe}
|
||||||
|
|
||||||
% TODO ANKI-MARKER
|
|
||||||
\begin{theorem}
|
\begin{theorem}
|
||||||
\label{thm:lec12:1}
|
\label{thm:lec12:1}
|
||||||
Suppose that $A \subseteq \cN$ is analytic.
|
Suppose that $A \subseteq \cN$ is analytic.
|
||||||
|
|
|
@ -1,11 +1,12 @@
|
||||||
\lecture{13}{2023-11-08}{}
|
\lecture{13}{2023-11-08}{}
|
||||||
|
\gist{%
|
||||||
% Recap
|
% Recap
|
||||||
$\LO = \{x \in 2^{\N\times \N} : x \text{ is a linear order}\} $.
|
$\LO = \{x \in 2^{\N\times \N} : x \text{ is a linear order}\} $.
|
||||||
$\LO \subseteq 2^{\N \times \N}$ is closed
|
$\LO \subseteq 2^{\N \times \N}$ is closed
|
||||||
and $\WO = \{x \in \LO: x \text{ is a wellordering}\} $
|
and $\WO = \{x \in \LO: x \text{ is a wellordering}\} $
|
||||||
is coanalytic in $\LO$.
|
is coanalytic in $\LO$.
|
||||||
% End Recap
|
% End Recap
|
||||||
|
}{}
|
||||||
|
|
||||||
Another way to code linear orders:
|
Another way to code linear orders:
|
||||||
|
|
||||||
|
@ -32,6 +33,8 @@ with $(f^{-1}(\{1\}), <)$.
|
||||||
and $[\alpha_i, \alpha_{i+1})$ to $(i,i+1)$.
|
and $[\alpha_i, \alpha_{i+1})$ to $(i,i+1)$.
|
||||||
\end{proof}
|
\end{proof}
|
||||||
|
|
||||||
|
% TODO ANKI-MARKER
|
||||||
|
|
||||||
\begin{definition}[\vocab{Kleene-Brouwer ordering}]
|
\begin{definition}[\vocab{Kleene-Brouwer ordering}]
|
||||||
Let $(A,<)$ be a linear order and $A$ countable.
|
Let $(A,<)$ be a linear order and $A$ countable.
|
||||||
We define the linear order $<_{KB}$ on $A^{<\N}$
|
We define the linear order $<_{KB}$ on $A^{<\N}$
|
||||||
|
|
Loading…
Reference in a new issue