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Commit 0d3c32ac authored by Luke Naylor's avatar Luke Naylor
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Correction Q->R plus Sebi wording suggestion

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......@@ -10,6 +10,7 @@
\newcommand{\QQ}{\mathbb{Q}}
\newcommand{\ZZ}{\mathbb{Z}}
\newcommand{\RR}{\mathbb{R}}
\newcommand{\chern}{\operatorname{ch}}
\newcommand{\lcm}{\operatorname{lcm}}
\newcommand{\gcd}{\operatorname{gcd}}
......@@ -28,12 +29,12 @@ Practical Methods for Finding Pseudowalls}
\section{Introduction}
[ref] shows that for any $\beta_0 \in \QQ$,
the vertical line $\{\sigma_{\alpha,\beta_0} \colon \alpha \in \QQ_{>0}\}$ only
[ref] shows that for any rational $\beta_0$,
the vertical line $\{\sigma_{\alpha,\beta_0} \colon \alpha \in \RR_{>0}\}$ only
intersects finitely many walls. A consequence of this is that if
$\beta_{-} \in \QQ$, then there can only be finitely many circular walls to the
$\beta_{-}$ is rational, then there can only be finitely many circular walls to the
left of the vertical wall $\beta = \mu$.
On the other hand, when $\beta_{-} \not\in \QQ$, [ref] showed that there are
On the other hand, when $\beta_{-}$ is not rational, [ref] showed that there are
infinitely many walls.
This dichotomy does not only hold for real walls, realised by actual objects in
......@@ -43,11 +44,11 @@ which satisfy certain numerical conditions which would be satisfied by any real
destabilizer, regardless of whether they are realised by actual elements of
$\bddderived(X)$.
Since real walls are a subset of pseudowalls, the $\beta_{-} \not\in \QQ$ case
Since real walls are a subset of pseudowalls, the irrational $\beta_{-}$ case
follows immediately from the corresponding case for real walls.
However, the $\beta_{-} \in \QQ$ case involves showing that the following
However, the rational $\beta_{-}$ case involves showing that the following
conditions only admit finitely many solutions (despite the fact that the same
conditions admit infinitely many solutions when $\beta_{-} \not\in \QQ$).
conditions admit infinitely many solutions when $\beta_{-}$ is irrational).
For a destabilizing sequence
......
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