From ce98427500966f2b1da721e55215a9af6d02c84f Mon Sep 17 00:00:00 2001 From: Luke Naylor <l.naylor@sms.ed.ac.uk> Date: Fri, 12 May 2023 15:12:02 +0100 Subject: [PATCH] Comment on general q case and split beta_min into (ir)rational cases --- main.tex | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/main.tex b/main.tex index ea245e7..6b844a9 100644 --- a/main.tex +++ b/main.tex @@ -15,11 +15,13 @@ \newcommand{\QQ}{\mathbb{Q}} \newcommand{\ZZ}{\mathbb{Z}} \newcommand{\RR}{\mathbb{R}} +\newcommand{\NN}{\mathbb{N}} \newcommand{\chern}{\operatorname{ch}} \newcommand{\lcm}{\operatorname{lcm}} \newcommand{\firsttilt}[1]{\mathcal{B}^{#1}} \newcommand{\bddderived}{\mathcal{D}^{b}} \newcommand{\centralcharge}{\mathcal{Z}} +\newcommand{\minorheading}[1]{{\noindent\normalfont\normalsize\bfseries #1}} \begin{document} @@ -741,6 +743,30 @@ In the other case, $q=\chern^{\beta}_1(F)$, it's the right hand sides of (eqn \ref{eqn:positive_rad_d_bound_betamin}) which match. +The more generic case, when $0 < q:=\chern_1{\beta}(E) < \chern_1^{\beta}(F)$ +for the bounds on $d$ in terms of $r$ is illustrated in figure +(\ref{fig:d_bounds_xmpl_gnrc_q}). +The question of whether there are pseudo-destabilizers of arbitrarily large +rank, in the context of the graph, comes down to whether there are points +$(r,d) \in \ZZ \oplus \frac{1}{m} \ZZ$ (with large $r$) +% TODO have a proper definition for pseudo-destabilizers/walls +that fit above the yellow line (ensuring positive radius of wall) but below the +blue and green (ensuring $\Delta(E), \Delta(G) > 0$). +These lines have the same assymptote at $r \to \infty$ +(eqns \ref{eqn:bgmlv2_d_bound_betamin}, +\ref{eqn:bgmlv3_d_bound_betamin}, +\ref{eqn:positive_rad_d_bound_betamin}). +The finiteness of these solutions will be entirely determined by whether $\beta$ +is rational or irrational, as covered next. + + +\minorheading{Rational $\beta$} + +Suppose $\beta = \frac{*}{n}$ for some $n \in \NN,* \in \ZZ$. + +\minorheading{Irrational $\beta$} + + \begin{figure} \centering \sageplot[ -- GitLab