You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
Copy file name to clipboardExpand all lines: blueprint/src/chapters/auxiliary.tex
+2
Original file line number
Diff line number
Diff line change
@@ -53,6 +53,7 @@ \section{Relations}
53
53
\end{itemize}
54
54
\end{definition}
55
55
\begin{proposition}[completing restricted orbits]
56
+
\uses{def:OrbitRestriction}
56
57
\label{prop:completing_restricted_orbits}
57
58
Let \( R : \tau\to\tau\to\Prop\) be a one-to-one relation, and let \( (t, f, \pi) \) be an orbit restriction for \(\field R \) over some type \(\sigma\).
58
59
Then there is a permutative relation \( T \) such that
@@ -82,6 +83,7 @@ \section{Relations}
82
83
Then there is a permutative relation \( S \) such that \( R \leq S \) and \(\coim S \subseteq\field R \cup s \).
83
84
\end{proposition}
84
85
\begin{proof}
86
+
\uses{prop:completing_restricted_orbits}
85
87
Define the orbit restriction \( (s, f, \pi) \) for \(\field R \) over \(\Unit\).
86
88
Note that for this to be defined, we used the inequality
If \(\#\tau\leq\#\mu\), then there are at most \(\#\mu\)-many enumerations of \(\tau\): enumerations are determined by an element of \(\kappa\) and a small subset of \(\kappa\times\tau\).
216
216
If \(\#\tau < \#\mu\), then there are strictly less than \(\#\mu\)-many enumerations of \(\tau\): use the same reasoning and apply \cref{prop:mk_subset_mk_lt_cof}.
217
217
\end{definition}
218
-
\begin{definition}[support]
219
-
\label{def:StrSupport}
220
-
\uses{def:Enumeration,def:Tree}
218
+
\begin{definition}[base support]
219
+
\label{def:BaseSupport}
220
+
\uses{def:Enumeration,def:NearLitter}
221
221
A \emph{base support} is a pair \( S = (S^\Atom, S^\NearLitter) \) where \( S^\Atom\) is an enumeration of atoms and \( S^\NearLitter\) is an enumeration of near-litters.
222
222
There are precisely \(\#\mu\) base supports.
223
-
223
+
\end{definition}
224
+
\begin{definition}[structural support]
225
+
\label{def:StrSupport}
226
+
\uses{def:BaseSupport,def:Tree}
224
227
A \emph{\(\beta\)-structural support} (or just \emph{\(\beta\)-support}) is a \(\beta\)-tree of base supports.
225
228
The type of \(\beta\)-supports is written \(\StrSupp_\beta\).
226
229
There are precisely \(\#\mu\) structural supports for any type index \(\beta\).
A \(\beta\)-approximation \(\psi\) is \emph{coherent} at \( (A, L_1, L_2) \) if:
169
169
\begin{itemize}
170
170
\item If \( L_1 \) is \( A \)-inflexible with inflexible \(\beta\)-path \( I = (\gamma, \delta, \varepsilon, B) \) and tangle \( t : \Tang_\delta\), then there is some \(\delta\)-allowable permutation \(\rho\) such that
Suppose that \(\psi\) is an approximation and \( L : \mathbb Z \to\Litter\) is a function satisfying the hypotheses of \cref{prop:BaseApprox.addOrbit}.
183
183
Let \(\chi\) be the extension produced by the structural version of this result.\footnote{We need the extension exactly as produced (as data), not an arbitrary extension satisfying the conclusion of the proposition.}
This proof just relies on the fact that if \( (\psi_B)_\delta(\supp(t)) = \rho(\supp(t)) \), then the same holds for every extension \(\chi\) of \(\psi\).\footnote{Maybe there's a better lemma to abstract out this idea for this and \cref{prop:StrApprox.chain}?}
188
188
\end{proof}
189
189
\begin{proposition}
190
-
\uses{def:Coherent}
191
-
\label{prop:Coherent.inv}
190
+
\uses{def:StrApprox.Coherent}
191
+
\label{prop:StrApprox.Coherent.inv}
192
192
If \(\psi\) is coherent, then \(\psi^{-1} \) is coherent.
Instead, if \( L_1 \) is \( A \)-flexible, then so is \( L_2 \) by coherence of \(\psi\), and so is \( L_3 \) by coherence of \(\chi\).
238
238
\end{proof}
239
239
\begin{proposition}
240
-
\uses{def:Coherent}
241
-
\label{prop:Coherent.deriv}
240
+
\uses{def:StrApprox.Coherent}
241
+
\label{prop:StrApprox.Coherent.deriv}
242
242
If \(\psi\) is a coherent \(\beta\)-approximation and \( A \) is a path \(\beta\tpath\beta' \), then \(\psi_A \) is a coherent \(\beta' \)-approximation.
243
243
\end{proposition}
244
244
\begin{proof}
245
-
\uses{prop:Coherent.inv}
245
+
\uses{prop:StrApprox.Coherent.inv}
246
246
Let \( (L_1, L_2) \in (\psi_A)_B^\Litter\).
247
247
Suppose that \( L_1 \) is \( B \)-inflexible with path \( (\gamma, \delta, \varepsilon, C) \) and \( t : \Tang_\delta\).
248
248
Then \( L_1 \) is \( A_B \)-inflexible with path \( (\gamma, \delta, \varepsilon, A_C) \) and the same tangle \( t \).
This same \(\rho\) can thus be used to establish coherence of \(\psi_A \) at \( (B, L_1, L_2) \).
254
254
255
-
Thus, by \cref{prop:Coherent.inv}, whenever \( L_2 \) is \( B \)-inflexible with path \( I \) and tangle \( t \), \( L_1 \) is also \( B \)-inflexible with path \( I \).
255
+
Thus, by \cref{prop:StrApprox.Coherent.inv}, whenever \( L_2 \) is \( B \)-inflexible with path \( I \) and tangle \( t \), \( L_1 \) is also \( B \)-inflexible with path \( I \).
256
256
So if \( L_1 \) is \( B \)-flexible, so is \( L_2 \), as required.
We say that a \(\beta\)-approximation \(\psi\)\emph{approximates} a \(\beta\)-allowable permutation \(\rho\) if \(\psi_A^\Litter\leq\rho_A^\Litter\) and \(\psi_A^\Atom\leq\rho_A^\Atom\) for each path \( A : \beta\tpath\bot\).
264
264
If \(\psi\) approximates \(\rho\) then \(\psi^n \) approximates \(\rho^n \) for each \( n : \mathbb Z \).\footnote{We should define what it means for a base approximation to approximate a near-litter permutation, and define this in terms of that.}
265
265
A \(\beta\)-approximation \(\psi\)\emph{exactly approximates} a \(\beta\)-allowable permutation \(\rho\) if \(\psi\) approximates \(\rho\), and in addition, if \( a \) is an atom and \( A : \beta\tpath\bot\), then \( a \notin\coim\psi_A^\Atom\) implies \(\rho(a)^\circ = \rho(a^\circ) \) and \(\rho^{-1}(a)^\circ = \rho^{-1}(a^\circ) \).
266
266
\end{definition}
267
267
\begin{definition}[freedom of action]
268
-
\uses{def:Approximates}
268
+
\uses{def:StrApprox.Approximates}
269
269
\label{def:FreedomOfAction}
270
270
We say that \emph{freedom of action} holds at a type index \(\delta\) if every coherent \(\delta\)-approximation exactly approximates some \(\delta\)-allowable permutation.
271
271
\end{definition}
@@ -289,7 +289,7 @@ \section{Proving freedom of action}
289
289
Then there is a coherent extension \(\chi\geq\psi\) with \( L \in\coim\chi_A^\Litter\).
Let \(\rho\) be a \(\delta\)-allowable permutation that \( (\psi_B)_\delta\) approximates.
294
294
Then for each \( n : \mathbb Z \), as \( (\psi^n_B)_\delta\) approximates \(\rho^n \), we obtain \( (\psi^n_B)_\delta(\supp(t)) = \rho^n(\supp(t)) \) as \( (\psi^n_B)_\delta\) is defined on all of \(\supp(t) \).\footnote{This should of course be its own lemma.}
295
295
Define \( L : \mathbb Z \to\Litter\) by \( L(n) = f_{\delta,\varepsilon}(\rho^n(t)) \).
@@ -316,7 +316,7 @@ \section{Proving freedom of action}
316
316
as required.\footnote{It might be helpful to abstract away the lemma \( (\psi^m_B)_\delta(\supp(\rho^n(t))) = \supp(\rho^{n+m}(t)) \) for the two places in the proof where this idea is used.}
317
317
\end{proof}
318
318
\begin{proposition}
319
-
\uses{def:Coherent}
319
+
\uses{def:StrApprox.Coherent}
320
320
\label{prop:StrApprox.chain}
321
321
If \( (\psi_i)_{i : I} \) is a chain of coherent approximations where \( I \) is a linear order, then the supremum \(\psi\) is coherent.
322
322
\end{proposition}
@@ -325,7 +325,7 @@ \section{Proving freedom of action}
325
325
\end{proof}
326
326
\begin{theorem}[freedom of action]
327
327
\uses{def:FreedomOfAction}
328
-
\label{thm:freedom_of_action}
328
+
\label{thm:StrApprox.foa}
329
329
Freedom of action holds at all type indices \(\beta\leq\alpha\).
330
330
\end{theorem}
331
331
\begin{proof}
@@ -351,6 +351,7 @@ \section{Proving freedom of action}
351
351
352
352
\section{Base actions}
353
353
\begin{definition}
354
+
\uses{def:NearLitter}
354
355
\label{def:Interference}
355
356
The \emph{interference} of near-litters \( N_1, N_2 \) is
356
357
\[\interf(N_1, N_2) = \begin{cases}
@@ -360,6 +361,7 @@ \section{Base actions}
360
361
which is a small set of atoms.
361
362
\end{definition}
362
363
\begin{definition}
364
+
\uses{def:Interference,def:BaseSupport}
363
365
\label{def:BaseAction}
364
366
A \emph{base action} is a pair \(\xi = (\xi^\Atom, \xi^\NearLitter) \) such that \(\xi^\Atom\) and \(\xi^\NearLitter\) are one-to-one relations of atoms and near-litters respectively (\cref{def:relation_props}), such that
Every base action \(\xi\) admits an extension \(\zeta\) satisfying
413
418
\[\forall N \in\coim\xi^\NearLitter,\,\LS(N) \setminus N \subseteq\coim\xi^\Atom\]
414
419
\end{proposition}
415
420
\begin{proof}
416
-
Without loss of generality (as extensions are transitive), let \(\xi\) satisfy the conclusion of \cref{prop:BaseAction.exists_outside}.
421
+
\uses{prop:BaseAction.exists_inside}
422
+
Without loss of generality (as extensions are transitive), let \(\xi\) satisfy the conclusion of \cref{prop:BaseAction.exists_inside}.
417
423
418
424
Let \( L \) be an arbitrary litter that whose litter set does not contain an atom in \(\im\xi^\Atom\) or \(\bigcup\im\xi^\NearLitter\).
419
425
Define an injection
@@ -430,20 +436,24 @@ \section{Base actions}
430
436
But then as \(\xi\) satisfies the conclusion of \cref{prop:BaseAction.exists_outside}, we have \( N_1 \setminus\LS(N_1^\circ) \subseteq\coim\xi^\Atom\), which again is a contradiction.
Apply \cref{prop:BaseAction.exists_inside} to \(\xi\) to obtain \(\xi_1 \); apply \cref{prop:BaseAction.exists_inside} again to \(\xi_1^{-1} \) to obtain \(\xi_2 \); apply \cref{prop:BaseAction.exists_outside} to \(\xi_2 \) to obtain \(\xi_3 \), and finally apply \cref{prop:BaseAction.exists_outside} again to \(\xi_3^{-1} \) to obtain \(\xi_4 \), our target.
438
446
\end{proof}
439
447
440
448
\section{Structural actions}
441
449
\begin{definition}
450
+
\uses{def:Tree,def:BaseAction,def:StrSupport}
442
451
\label{def:StrAction}
443
452
For a type index \(\beta\), a \emph{\(\beta\)-action} is a \(\beta\)-tree of base actions.
444
453
We define an action of \(\beta\)-actions \(\xi\) on \(\beta\)-supports \( S \) by \( (\xi(S))_A = \xi_A(S_A) \).
445
454
\end{definition}
446
455
\begin{definition}
456
+
\uses{def:StrAction,def:Inflexible}
447
457
\label{def:StrAction.Coherent}
448
458
A \(\beta\)-action \(\xi\) is \emph{coherent} at \( (A, L_1, L_2) \) if:
449
459
\begin{itemize}
@@ -457,6 +467,7 @@ \section{Structural actions}
457
467
We say that \(\xi\) is \emph{coherent} if whenever \( (L_1, L_2) \in\xi_A^\Litter\), \(\xi\) is coherent at \( (A, L_1, L_2) \).
458
468
\end{definition}
459
469
\begin{definition}
470
+
\uses{def:StrAction,def:StrApprox.Coherent}
460
471
\label{def:FlexApprox}
461
472
Let \( A : \beta\tpath\bot\).
462
473
An \emph{\( A \)-flexible approximation} of a base action \(\xi\) is a base approximation \(\psi\) such that
Finally, if \( a_2 \notin\coim S \) and \( a_2^\circ\neq N_2^\circ\), then \( a_2 \notin N_2 \), since \( a_2 \in N_2 \) would imply \( a_2 \in N_2 \symmdiff\LS(N_2^\circ) \), contradicting the fact that \(\xi\) is nice.
521
534
\end{proof}
522
535
\begin{definition}[approximates]
536
+
\uses{def:StrAction,def:ModelData}
523
537
\label{def:StrAction.Approximates}
524
538
We say that a \(\beta\)-action \(\xi\)\emph{approximates} a \(\beta\)-allowable permutation \(\rho\) if \(\xi_A^\NearLitter\leq\rho_A^\NearLitter\) and \(\xi_A^\Atom\leq\rho_A^\Atom\) for each path \( A : \beta\tpath\bot\).\footnote{Again, we should define what it means for a base action to approximate a near-litter permutation, and define this in terms of that.}
Let \(\xi\) be a coherent \(\beta\)-action, and let \(\psi\) be a flexible approximation for it, which exists by \cref{prop:exists_flexApprox}.
580
-
Then apply \cref{thm:freedom_of_action} (freedom of action) to \(\psi\) to obtain a \(\beta\)-allowable permutation \(\rho\) that \(\psi\) exactly approximates.
600
+
Then apply \cref{thm:StrApprox.foa} (freedom of action) to \(\psi\) to obtain a \(\beta\)-allowable permutation \(\rho\) that \(\psi\) exactly approximates.
581
601
Finally, appeal to \cref{prop:approximates_of_flexApprox} to conclude that \(\xi\) approximates \(\rho\).
0 commit comments