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luke naylor latex documents
research
Max Destabilizer Rank
Commits
8f28b259
Commit
8f28b259
authored
1 year ago
by
Luke Naylor
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Remove all references to the Delta(u,v-u)>=0 condition
parent
b3f3fc6a
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main.tex
+3
-118
3 additions, 118 deletions
main.tex
with
3 additions
and
118 deletions
main.tex
+
3
−
118
View file @
8f28b259
...
...
@@ -169,17 +169,11 @@ surfaces and $\PP^2$.
which has the same tilt slope as
$
v
$
:
$
\nu
_{
\alpha
,
\beta
}
(
u
)
=
\nu
_{
\alpha
,
\beta
}
(
v
)
$
.
\noindent
Furthermore the following
Bogomolov-Gieseker
inequalities are satisfied:
Furthermore the following inequalities are satisfied:
\begin{itemize}
\item
$
\Delta
(
u
)
\geq
0
$
\item
$
\Delta
(
v
-
u
)
\geq
0
$
\item
$
\Delta
(
u
)
+
\Delta
(
v
-
u
)
\leq
\Delta
(
v
)
$
\end{itemize}
\noindent
And finally these two conditions are satisfied:
\begin{itemize}
\item
$
\chern
_
1
^{
\beta
}
(
u
)
\geq
0
$
\item
$
\chern
_
1
^{
\beta
}
(
v
-
u
)
\geq
0
$
\item
$
0
\leq
\chern
_
1
^{
\beta
}
(
u
)
\leq
\chern
_
1
^{
\beta
}
(
v
)
$
\end{itemize}
Note
$
u
$
does not need to be a Chern character of an actual sub-object of some
...
...
@@ -498,7 +492,7 @@ Fixing attention on the only possible case (2), illustrated in Fig
\ref
{
fig:correct-hyperbol-intersection
}
.
$
P
$
is on the left of
$
V
_{
\pm
u
}$
(first part of consequence 2), so
$
u
$
must
have positive rank (consequence 1)
to ensure that
$
\chern
_
1
^{
\beta
{
P
}
}
\geq
0
$
(since the pseudo-wall passed over
to ensure that
$
\chern
_
1
^{
\beta
(
P
)
}
\geq
0
$
(since the pseudo-wall passed over
$
P
$
).
Furthermore,
$
P
$
being on the left of
$
V
_
u
$
implies
$
\chern
_
1
^{
\beta
{
P
}}
(
u
)
\geq
0
$
,
...
...
@@ -845,85 +839,6 @@ This condition amounts to:
d
&
\geq
\beta
_{
-
}
q +
\frac
{
1
}{
2
}
\beta
_{
-
}^
2r
\end{align}
\subsubsection
{
\texorpdfstring
{
$
\Delta
(
u,v
-
u
)
\geq
0
$
}{
Δ(u,v-u) ≤ 0
}
}
\label
{
subsect-d-bound-bgmlv1
}
Writing the condition in terms of the twisted chern characters
for
$
u
$
and
$
v
$
at
$
\beta
$
(
$
(
r,
\chern
_
1
^{
\beta
}
(
u
)
,
\chern
_
2
^{
\beta
}
(
u
))
$
and
$
(
R
-
r,
\chern
_
1
^{
\beta
}
(
v
-
u
)
,
\chern
_
2
^{
\beta
}
(
v
-
u
))
$
) yields:
\begin{equation}
\label
{
eqn:bgmlv1-pt1
}
(R-r)
\chern
_
2
^{
\beta
}
(u)
\leq
\chern
_
1
^{
\beta
}
(u)
\chern
_
1
^{
\beta
}
(v-u)
- r
\chern
_
2
^{
\beta
}
(v-u)
\end{equation}
Which rearranges to (using additivity of
$
\chern
_
2
^{
\beta
}$
):
\begin{equation}
\label
{
eqn:bgmlv1-pt2
}
(R-2r)
\chern
_
2
^{
\beta
}
(u)
\leq
\chern
_
1
^{
\beta
}
(u)
\chern
_
1
^{
\beta
}
(v-u)
- r
\chern
_
2
^{
\beta
}
(v)
\end{equation}
With
$
u
$
satisfying the condition given by equation
\ref
{
eqn-cintermsofm
}
,
we note that
$
\chern
_
1
^{
\beta
}
(
u
)
,
\chern
_
1
^{
\beta
}
(
v
-
u
)
\geq
0
$
.
In the special case with
$
P
=(
\beta
_{
-
}
,
0
)
$
,
we have
$
\chern
_
2
^{
\beta
_{
-
}}
(
v
)=
0
$
, and we can assume
equation
$
\chern
_
2
^{
\beta
_{
-
}}
(
u
)
>
0
$
(eqn
\ref
{
eqn:radius-cond-betamin
}
)
in the context of our problem.
Finally,
$
r>
0
$
as per the statement of the problem, so the right-hand-side
of equation
\ref
{
eqn:bgmlv1-pt1
}
is always greater than, or equal, to zero.
And so, when
$
P
\coloneqq
(
\beta
_{
-
}
,
0
)
$
, this condition
$
\Delta
(
u,v
-
u
)
\geq
0
$
is
always satisfied when
$
2
r
\geq
R
$
, provided that the other conditions of the
problem statement (
\ref
{
subsect:problem-statement-2
}
) hold.
However, when
$
2
r<R
$
, this condition does add potentially independent condition
of the others:
\begin{equation}
\label
{
eqn:bgmlv1-pt3
}
\chern
_
2
^{
\beta
}
(u)
\leq
\frac
{
\chern
_
1
^{
\beta
}
(u)
\chern
_
1
^{
\beta
}
(v-u)
- r
\chern
_
2
^{
\beta
}
(v)
}
{
R-2r
}
,
\qquad
2r<R
\end{equation}
Expressed in terms of
$
d
$
and
$
q
$
:
\begin{equation}
\label
{
eqn:bgmlv1-pt4
}
d
\leq
\beta
_{
-
}
q
+
\frac
{
1
}{
2
}{
\beta
_{
-
}}^
2r
+
\frac
{
q(
\chern
_
1
^{
\beta
}
(v)-q)
- r
\chern
_
2
^{
\beta
}
(v)
}
{
R-2r
}
,
\qquad
2r<R
\end{equation}
\subsubsection
{
\texorpdfstring
{
$
\Delta
(
E
)
\geq
0
$
...
...
@@ -1203,17 +1118,6 @@ vertical wall (TODO as discussed in ref).
\phantom
{
+
}&
% to keep terms aligned
&
\qquad\text
{
when
\:
}
r > 0
\label
{
eqn:radiuscond
_
d
_
bound
_
betamin
}
\\
d
&
\leq
&
\frac
{
1
}{
2
}{
\beta
}^
2r
&
+
\beta
q
+
&
\frac
{
q(
\chern
_
1
^{
\beta
}
(v)-q)
}
{
R-2r
}
,
&
\qquad\text
{
when
\:
}
0 < r <
\frac
{
R
}{
2
}
\label
{
eqn:bgmlv1
_
d
_
bound
_
betamin
}
\\
d
&
\leq
&
\sage
{
bgmlv2
_
d
_
upperbound
_
linear
_
term
}
...
...
@@ -1279,18 +1183,6 @@ def plot_d_bound(
):
# Equations to plot imminently representing the bounds on d:
eq1 = (
(
beta
^
2*r/2
+ beta*q
+ q*(chb1v - q)/(R-2*r)
)
.subs(chb1v == v
_
example.twist(beta
_
min(v
_
example)).ch[1])
.subs(beta = beta
_
min(v
_
example))
.subs(q == q
_
example)
.subs(R == v
_
example.ch[0])
)
eq2 = (
bgmlv2
_
d
_
upperbound
.subs(R == v
_
example.ch[0])
...
...
@@ -1337,13 +1229,6 @@ def plot_d_bound(
linestyle = "dotted",
legend
_
label=r"lower bound:
$
\mathrm
{
ch
}_
2
^{
\beta
_{
-
}}
(
u
)
>
0
$
"
)
+ plot(
eq1,
(r,0,v
_
example.ch[0]/2),
color='red',
linestyle = "dashed",
legend
_
label=r"upper bound:
$
\Delta
(
u,v
)
\geq
0
$
"
)
)
example
_
bounds
_
on
_
d
_
plot.ymin(ymin)
example
_
bounds
_
on
_
d
_
plot.ymax(ymax)
...
...
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