Skip to content
Snippets Groups Projects
Commit 90dd4611 authored by Luke Naylor's avatar Luke Naylor
Browse files

Justify parts of first problem

parent dec87274
No related branches found
No related tags found
No related merge requests found
......@@ -562,16 +562,36 @@ are trying to solve for.
Fix a Chern character $v$ with positive rank, $\Delta(v) \geq 0$,
and $\beta_{-}(v) \in \QQ$.
The goal is to find all pseudo-semistabilizers $u=(r,c\ell,d\ell^2)$
The goal is to find all pseudo-semistabilizers $u$
which give circular pseudo-walls containing some fixed point
$P\in\Theta_v^-$.
With the added restriction that $u$ `destabilizes' $v$ moving `inwards', that is,
$\nu(u)>\nu(v)$ inside the circular pseudo-wall
(`outward' destabilizers can be recovered as $v-u$).
$\nu(u)>\nu(v)$ inside the circular pseudo-wall.
\end{problem}
This will give all pseudo-walls between the chamber corresponding to Gieseker
stability and the stability condition corresponding to $P$.
\end{problem}
The purpose of the final `direction' condition is because, up to that point,
semistabilizers are not distinguished from their corresponding quotients:
Suppose $E\hookrightarrow F\twoheadrightarrow G$, then the tilt slopes
$\nu_{\alpha,\beta}$
are strictly increasing, strictly decreasing, or equal across the short exact
sequence (consequence of the see-saw principle).
In this case, $\chern(E)$ is a pseudo-semistabilizer of $\chern(F)$, if and
only if $\chern(G)$ is a pseudo-semistabilizer of $\chern(F)$.
The numerical inequalities in the definition for pseudo-semistabilizer cannot
tell which of $E$ or $G$ is the subobject.
However what can be distinguished is the direction across the wall that
$\chern(E)$ or $\chern(G)$ destabilizes $\chern(F)$
(they will each destabilize in the opposite direction to the other).
The `inwards' semistabilizers are preferred because we are moving from a
typically more familiar chamber
(the stable objects of Chern character $v$ in the outside chamber will only be
Gieseker stable sheaves).
Also note that this last restriction does not remove any pseudo-walls found,
and if we do want to recover `outwards' semistabilizers, we can simply take
$v-u$ for each solution $u$ of the problem.
\begin{problem}[all `left' pseudo-walls]
\label{problem:problem-statement-2}
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment