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  pdftitle={The Trinity as Limit Topological Modal Logic of the Monistic Structure},
  pdfauthor={Paul Koop},
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\title{The Trinity as Limit\\
Topological Modal Logic of the Monistic Structure}
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\providecommand{\subtitle}[1]{% add subtitle to \maketitle
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\makeatother
\subtitle{Topological Modal Logic of the Monistic Structure}
\author{Paul Koop}
\date{}

\begin{document}
\maketitle
\begin{abstract}
In modal5.md, the definitions T := \{ x \textbar{} U \textless{} x
\textless{} S \}, U := lim\_\{x → inf\} T, and S := lim\_\{x → sup\} T
appear. These definitions are informal. They use a metric limit concept
that is not readily available in first-order modal logic. The present
treatise provides a precise modal-logical version of this discourse. It
extends S5 by a limit operator L with neighborhood semantics, defines U
:= L\_inf T and S := L\_sup T, and proves: In S5+SP+L, the Trinitarian
formula holds. The Trinity thus proves to be a limit structure, not a
substantial object. The treatise refines the discourse of the limit, it
does not replace it.
\end{abstract}

{
\hypersetup{linkcolor=}
\setcounter{tocdepth}{3}
\tableofcontents
}
\emph{Past and future are horizons of knowledge.}\\
\emph{The present is the locus of reality.}\\
\emph{Nothing that was, is lost.}

\section{Preface: The Informal Limit
Definition}\label{preface-the-informal-limit-definition}

In \texttt{modal5.md}, the Trinity is introduced as a limit structure.
The central definitions are:

\[T := \{ x \mid U < x < S \}\] \[U := \lim_{x \to \inf} T\]
\[S := \lim_{x \to \sup} T\] \[Tr := U \land T \land S\]

These definitions are \textbf{informal}. They use a \textbf{metric limit
concept} that is not readily available in first-order modal logic. The
expression \(\lim_{x \to \inf} T\) presupposes a metric or at least an
order topology on \(T\) --- neither of which is self-evident in pure
predicate logic with modal operators.

The present treatise provides a \textbf{precise modal-logical version}
of this discourse. It extends S5 by a \textbf{limit operator}
\(\mathcal{L}\) with neighborhood semantics, defines \(U\) and \(S\) as
limits in the sense of this operator, and proves: In
S5+SP+\(\mathcal{L}\), the Trinitarian formula holds.

The central claim of this treatise is:

\begin{quote}
\textbf{The Trinity was always thought as a limit structure. The
treatise refines this discourse, it does not replace it. The limit
concept is translated from a metric into a modal-logical language ---
without changing the substance of the original intuition.}
\end{quote}

The investigation remains faithful to the methodological
self-understanding of \texttt{modal5.md}: It shows a
\textbf{formalization}, not a new metaphysical thesis. What it shows is
that the discourse of the limit can be precisely grasped in modal logic.

\section{Topological Modal Logic: A Brief
Introduction}\label{topological-modal-logic-a-brief-introduction}

\subsection{Why Topology?}\label{why-topology}

Classical modal logic S5 uses an \textbf{accessibility relation} \(R\)
between possible worlds. In S5, this relation is an equivalence
relation. It allows us to speak about necessity and possibility, but it
does \textbf{not} allow us to speak about \textbf{convergence} or
\textbf{limits}.

For the discourse of limits, we need a \textbf{topological structure}.
Topological modal logic extends S5 by such a structure.

\subsection{Neighborhood Semantics}\label{neighborhood-semantics}

\textbf{Neighborhood semantics} is a generalization of Kripke semantics.
Instead of an accessibility relation \(R\), it uses a
\textbf{neighborhood function} \(N\) that assigns to each world \(w\) a
set of sets of worlds:

\[N : W \to \mathcal{P}(\mathcal{P}(W))\]

\(N(w)\) is the set of \textbf{neighborhoods} of \(w\). A neighborhood
of \(w\) is a set of worlds that ``surrounds'' \(w\).

\textbf{Intuition:} \(N(w)\) describes which sets of worlds lie in the
vicinity of \(w\).

\subsection{The Neighborhood Operator}\label{the-neighborhood-operator}

The \textbf{neighborhood operator} \(\mathcal{N}\) is defined by:

\[\mathcal{N} p @ w \iff \{ v \mid p @ v \} \in N(w)\]

\textbf{Reading:} ``\(\mathcal{N} p\) holds in \(w\)'' exactly when the
set of worlds in which \(p\) holds is a neighborhood of \(w\).

\textbf{Properties:}

\begin{itemize}
\tightlist
\item
  \(\mathcal{N}\) is \textbf{not} normal --- it does not distribute over
  implication.
\item
  \(\mathcal{N}\) allows \textbf{finer} distinctions than \(\Box\).
\item
  In S5: \(\Box p \to \mathcal{N} p\), but not conversely.
\end{itemize}

\subsection{Convergence}\label{convergence}

A \textbf{convergence structure} on \(W\) is a family of filters
\(\mathcal{F}_w\) for each world \(w\). A \textbf{filter} is a set of
subsets of \(W\) closed under finite intersections and supersets.

\textbf{Intuition:} \(\mathcal{F}_w\) describes which sets of worlds lie
``eventually'' in the vicinity of \(w\).

\textbf{Convergence:} A sequence of worlds \((w_n)\) converges to \(w\)
if for every neighborhood \(A \in N(w)\), almost all \(w_n\) lie in
\(A\).

\subsection{Limit Operators}\label{limit-operators}

A \textbf{limit operator} \(\mathcal{L}\) is defined by:

\[\mathcal{L} p @ w \iff \text{there is a sequence } (w_n) \to w \text{ with } p @ w_n \text{ for almost all } n\]

\textbf{Reading:} ``\(\mathcal{L} p\) holds in \(w\)'' exactly when
\(p\) holds in almost all worlds of a sequence converging to \(w\).

\textbf{Important:} \(\mathcal{L}\) is \textbf{not} a normal operator.
It does not satisfy the Kripke axiom \(K\). Instead, it satisfies
\textbf{convergence axioms}.

\section{The Limit Operator L: Definition, Axioms, Tableau
Rules}\label{the-limit-operator-l-definition-axioms-tableau-rules}

\subsection{Definition}\label{definition}

We extend the language of S5 by a \textbf{binary limit operator}
\(\mathcal{L}_{\inf}\) and \(\mathcal{L}_{\sup}\):

\begin{itemize}
\tightlist
\item
  \(\mathcal{L}_{\inf} p\) means: ``p holds in the lower limit.''
\item
  \(\mathcal{L}_{\sup} p\) means: ``p holds in the upper limit.''
\end{itemize}

\textbf{Semantics:}

\[\mathcal{L}_{\inf} p @ w \iff \text{there is a monotonically decreasing sequence } (w_n) \to w \text{ with } p @ w_n\]

\[\mathcal{L}_{\sup} p @ w \iff \text{there is a monotonically increasing sequence } (w_n) \to w \text{ with } p @ w_n\]

\subsection{Axioms}\label{axioms}

\[\begin{aligned}
L1 &:= \Box(\mathcal{L}_{\inf} p \rightarrow \Diamond p) \\
L2 &:= \Box(\mathcal{L}_{\sup} p \rightarrow \Diamond p) \\
L3 &:= \Box(\mathcal{L}_{\inf}(p \rightarrow q) \rightarrow (\mathcal{L}_{\inf} p \rightarrow \mathcal{L}_{\inf} q)) \\
L4 &:= \Box(\mathcal{L}_{\sup}(p \rightarrow q) \rightarrow (\mathcal{L}_{\sup} p \rightarrow \mathcal{L}_{\sup} q)) \\
L5 &:= \Box(\mathcal{L}_{\inf} p \rightarrow \mathcal{N} p) \\
L6 &:= \Box(\mathcal{L}_{\sup} p \rightarrow \mathcal{N} p) \\
L7 &:= \Box(\mathcal{N} p \rightarrow p)
\end{aligned}\]

\textbf{Explanation:}

\begin{itemize}
\tightlist
\item
  L1, L2: Limits are possible.
\item
  L3, L4: Limit operators distribute over implication.
\item
  L5, L6: Limits imply neighborhood.
\item
  L7: Neighborhood implies actuality.
\end{itemize}

\subsection{Tableau Rules}\label{tableau-rules}

\[\begin{aligned}
& (\neg\mathcal{L}_{\inf}) & \frac{\neg\mathcal{L}_{\inf} A}{\Diamond\neg A} \\
& (\neg\mathcal{L}_{\sup}) & \frac{\neg\mathcal{L}_{\sup} A}{\Diamond\neg A} \\
& (\mathcal{L}_{\inf}) & \frac{\mathcal{L}_{\inf} A}{\mathcal{N} A} \\
& (\mathcal{L}_{\sup}) & \frac{\mathcal{L}_{\sup} A}{\mathcal{N} A} \\
& (\mathcal{N}) & \frac{\mathcal{N} A}{A}
\end{aligned}\]

\textbf{Important:} The rules for \(\mathcal{L}_{\inf}\) and
\(\mathcal{L}_{\sup}\) are \textbf{one-sided} --- they only allow the
transition from limit to neighborhood, not the other way.

\section{Reconstruction of U and S}\label{reconstruction-of-u-and-s}

\subsection{The Informal Definitions}\label{the-informal-definitions}

In \texttt{modal5.md}:

\[U := \lim_{x \to \inf} T\] \[S := \lim_{x \to \sup} T\]

These definitions use a \textbf{metric} limit concept. We translate them
into topological modal logic.

\subsection{The Formal Definitions}\label{the-formal-definitions}

\[\boxed{U := \mathcal{L}_{\inf} T}\]
\[\boxed{S := \mathcal{L}_{\sup} T}\]

\textbf{Explanation:}

\begin{itemize}
\tightlist
\item
  \(U\) is the \textbf{lower limit} of Totality \(T\). It is what comes
  closest to the ``beginning.''
\item
  \(S\) is the \textbf{upper limit} of Totality \(T\). It is what comes
  closest to the ``end.''
\end{itemize}

\textbf{Important:} \(U\) and \(S\) are \textbf{not elements} of \(T\).
They are limits in the sense of the operator \(\mathcal{L}\).

\subsection{Totality T}\label{totality-t}

\[\boxed{T := \{ x \mid U < x < S \}}\]

In modal-logical language:

\[\boxed{T := \{ x \mid \neg\mathcal{L}_{\inf}\neg Tr(x) \land \neg\mathcal{L}_{\sup}\neg Tr(x) \}}\]

\textbf{Explanation:} \(T\) is the set of \(x\) for which: \(x\) lies
``between'' \(U\) and \(S\), i.e., \(x\) is not itself a limit, but an
element of the open interval.

\subsection{The Trinity}\label{the-trinity}

\[\boxed{Tr := U \land T \land S}\]

\section{Proof of the Trinity in
S5+SP+L}\label{proof-of-the-trinity-in-s5spl}

\subsection{The Proof}\label{the-proof}

\textbf{Theorem L-A:} In S5+SP+\(\mathcal{L}\), \(\Box\forall x\,Tr(x)\)
holds.

\textbf{Proof:}

\begin{enumerate}
\def\labelenumi{\arabic{enumi}.}
\tightlist
\item
  According to \texttt{modal5.md}, in S5+SP: \(\Box\forall x\,Tr(x)\)
  --- but with the informally defined \(Tr\).
\item
  We must show that the formal definition of \(Tr\) with \(\mathcal{L}\)
  yields the same structure.
\end{enumerate}

\textbf{Step 1:} From ASP3: \(\forall x\,Tr(x) @ w_{\text{super}}\).

\textbf{Step 2:} From ASP4: For all \(v\) with \(w_{\text{super}} R v\),
\(\forall x\,Tr(x) @ v\).

\textbf{Step 3:} We show that from
\(\forall x\,Tr(x) @ w_{\text{super}}\) follows:
\(\mathcal{L}_{\inf} T @ w_{\text{super}}\) and
\(\mathcal{L}_{\sup} T @ w_{\text{super}}\).

\begin{itemize}
\tightlist
\item
  \textbf{Proof of \(\mathcal{L}_{\inf} T\):} Consider the monotonically
  decreasing sequence
  \(w_{\text{super}} \supseteq w_1 \supseteq w_2 \supseteq \dots\), in
  which each \(w_i\) contains the Trinity in a smaller ``section.''
  Since \(Tr\) holds in \(w_{\text{super}}\) and \(T\) is the open
  interval, \(T\) holds in almost all \(w_i\). Hence
  \(\mathcal{L}_{\inf} T @ w_{\text{super}}\).
\item
  \textbf{Proof of \(\mathcal{L}_{\sup} T\):} Analogously with a
  monotonically increasing sequence.
\end{itemize}

\textbf{Step 4:} From L5, L6, and L7:
\(\mathcal{N} T @ w_{\text{super}}\) and \(T @ w_{\text{super}}\).

\textbf{Step 5:} From Steps 3 and 4:
\(U \land T \land S @ w_{\text{super}}\), i.e.,
\(Tr @ w_{\text{super}}\).

\textbf{Step 6:} Since \(w_{\text{super}}\) is accessible to all worlds
(ASP5), \(Tr\) holds in all worlds. Hence \(\Box\forall x\,Tr(x)\).

q.e.d.

\subsection{The Structure of the
Proof}\label{the-structure-of-the-proof}

The proof shows:

\begin{itemize}
\tightlist
\item
  The formal definition of \(U\) and \(S\) as limits is
  \textbf{compatible} with the informal definition.
\item
  The Trinitarian formula follows in S5+SP+\(\mathcal{L}\) exactly as in
  S5+SP.
\item
  The topological extension adds \textbf{no new metaphysical
  assumptions} --- it only refines the language.
\end{itemize}

\section{Comparison with the Original
Definition}\label{comparison-with-the-original-definition}

\subsection{The Informal Definition}\label{the-informal-definition}

\[U := \lim_{x \to \inf} T\]

\textbf{What it provides:}

\begin{itemize}
\tightlist
\item
  It gives an intuitive idea: \(U\) is the lower limit of \(T\).
\item
  It is mathematically intuitive.
\item
  But it is \textbf{not formal} --- it presupposes a metric.
\end{itemize}

\subsection{The Formal Definition}\label{the-formal-definition}

\[U := \mathcal{L}_{\inf} T\]

\textbf{What it provides:}

\begin{itemize}
\tightlist
\item
  It is formulated in a precise modal-logical language.
\item
  It uses a limit operator \(\mathcal{L}\) whose semantics are clearly
  defined.
\item
  It allows the proof of the Trinitarian formula to be conducted
  \textbf{formally}.
\end{itemize}

\subsection{What Remains the Same}\label{what-remains-the-same}

The \textbf{structure} of the definition is the same:

\begin{itemize}
\tightlist
\item
  \(U\) is the lower limit of \(T\).
\item
  \(S\) is the upper limit of \(T\).
\item
  \(T\) is the open interval between \(U\) and \(S\).
\end{itemize}

The \textbf{intuition} is the same:

\begin{itemize}
\tightlist
\item
  The Trinity is a limit structure.
\item
  The three aspects are not separate substances, but perspectives on the
  same reality.
\end{itemize}

\subsection{What Changes}\label{what-changes}

The \textbf{language} changes:

\begin{itemize}
\tightlist
\item
  Instead of a metric limit, we use a topological limit.
\item
  Instead of a metric, we use a neighborhood structure.
\item
  Instead of a number line, we use a modal-logical frame.
\end{itemize}

The \textbf{rigor} changes:

\begin{itemize}
\tightlist
\item
  The proof is now conducted \textbf{formally}.
\item
  The definitions are \textbf{precise}.
\item
  The dependencies are \textbf{explicit}.
\end{itemize}

\section{What Follows? The Trinity Is a Limit, Not an
Object}\label{what-follows-the-trinity-is-a-limit-not-an-object}

\subsection{The Central Insight}\label{the-central-insight}

The Trinity is \textbf{not an object}. It is \textbf{not a thing} among
things. It is a \textbf{limit} --- what stands at the end of a sequence
without itself being an element of the sequence.

\textbf{Formally:} \(U\) and \(S\) are not elements of \(T\). They are
limits in the sense of \(\mathcal{L}\).

\textbf{Metaphysically:} The Trinity is not an additional entity. It is
the \textbf{structure} of Totality itself.

\subsection{Consequences}\label{consequences}

\textbf{Consequence 1:} The Trinity cannot be ``found'' like an object.
It can only be \textbf{thought} as a limit.

\textbf{Consequence 2:} The Trinity is \textbf{not local}. It is not at
a particular place or time. It is a \textbf{global structure}.

\textbf{Consequence 3:} The Trinity is \textbf{not substantial}. It is
not a ``being,'' but a \textbf{form}. It is what remains when all
substances are subtracted.

\subsection{The Relation to Tradition}\label{the-relation-to-tradition}

Classical Trinitarian doctrine speaks of ``three persons'' and ``one
essence.'' The present treatise shows: This way of speaking can be
\textbf{precisely} grasped --- but not as a statement about substances,
but as a statement about \textbf{limits}.

\begin{itemize}
\tightlist
\item
  ``Three persons'' corresponds to the three limits \(U\), \(T\), \(S\).
\item
  ``One essence'' corresponds to the one structure constituted by the
  three limits.
\end{itemize}

\section{Open Questions: Which Topology Is the Right
One?}\label{open-questions-which-topology-is-the-right-one}

\subsection{The Question}\label{the-question}

The treatise has used \textbf{one} topology: neighborhood semantics with
convergence structure. But there are \textbf{many} possible topologies:

\begin{itemize}
\tightlist
\item
  The \textbf{discrete} topology.
\item
  The \textbf{metric} topology.
\item
  The \textbf{order} topology.
\item
  The \textbf{weak} topology.
\item
  The \textbf{product} topology.
\end{itemize}

\textbf{Which is the right one?}

\subsection{Possible Answers}\label{possible-answers}

\textbf{Answer 1:} Neighborhood semantics is the \textbf{weakest}
topology that allows the discourse of limits. It is therefore the
\textbf{minimal} choice.

\textbf{Answer 2:} The \textbf{order topology} is the natural topology
for Totality \(T\), because \(T\) already has an order.

\textbf{Answer 3:} The \textbf{weak} topology (also: weak convergence)
is the right one, because it is the \textbf{weakest} topology in which
the Trinitarian formula can be derived.

\textbf{Answer 4:} There is no ``right'' topology. The choice depends on
metaphysical or physical preferences. We stand at the beginning of
infinity.

\subsection{What We Have Not Shown}\label{what-we-have-not-shown}

We have \textbf{not} shown that neighborhood semantics is the only
possible topology. We have only shown that it is \textbf{sufficient}.

The question of the \textbf{minimality} of the topology remains open. It
is the subject of \textbf{Modal 9} and beyond.

\section{Conclusion: What Has Been
Shown?}\label{conclusion-what-has-been-shown}

The present investigation has shown:

\begin{enumerate}
\def\labelenumi{\arabic{enumi}.}
\item
  \textbf{The informal limit definition from modal5.md can be translated
  into a precise modal-logical language.} The limit operator
  \(\mathcal{L}\) with neighborhood semantics accomplishes this
  translation.
\item
  \textbf{In S5+SP+\(\mathcal{L}\), the Trinitarian formula holds.} The
  topological extension is sufficient.
\item
  \textbf{The Trinity is a limit, not an object.} It is the structure of
  Totality itself, not an additional entity.
\item
  \textbf{The formal definition is compatible with the informal
  definition.} It does not replace it, it refines it.
\end{enumerate}

The central claim of this treatise is:

\begin{quote}
\textbf{The Trinity was always thought as a limit structure. The
treatise refines this discourse, it does not replace it. The limit
concept is translated from a metric into a modal-logical language ---
without changing the substance of the original intuition.}
\end{quote}

The question of which topology is the right one remains open. It is the
subject of further investigations.

\section{Appendix A: The Axioms in an
Overview}\label{appendix-a-the-axioms-in-an-overview}

\subsection{Basic Axioms (from
modal5.md)}\label{basic-axioms-from-modal5.md}

\[\begin{aligned}
A1 &:= \Box\neg\exists x\exists y\, FundamentallySeparated(x,y) \\
A4 &:= \Diamond\exists w\, World(w) \\
A11 &:= \forall w \left( \text{WorldSeparatedFromConsciousness}(w) \leftrightarrow \neg \exists c (Consciousness(c) \land c(w)) \right) \\
A12 &:= \forall p. \text{Experienceable}(p) \leftrightarrow \exists w. Realized(w, p) \\
A13 &:= \Box\forall x(T(x) \rightarrow U(x)) \\
A14 &:= \Box\forall x(U(x) \rightarrow S(x)) \\
A15 &:= \Box\forall x(S(x) \rightarrow T(x))
\end{aligned}\]

\subsection{Superposition Axioms (from
modal5.md)}\label{superposition-axioms-from-modal5.md}

\[\begin{aligned}
ASP1 &:= C @ w_{\text{super}} \\
ASP2 &:= \forall v (w_{\text{super}} R v \rightarrow (C @ v \leftrightarrow v = w_{\text{super}})) \\
ASP3 &:= \forall x\,Tr(x) @ w_{\text{super}} \\
ASP4 &:= \forall v (w_{\text{super}} R v \rightarrow \forall x\,Tr(x) @ v) \\
ASP5 &:= \forall v (v \neq w_{\text{super}} \rightarrow w_{\text{super}} R v)
\end{aligned}\]

\subsection{Limit Axioms (new)}\label{limit-axioms-new}

\[\begin{aligned}
L1 &:= \Box(\mathcal{L}_{\inf} p \rightarrow \Diamond p) \\
L2 &:= \Box(\mathcal{L}_{\sup} p \rightarrow \Diamond p) \\
L3 &:= \Box(\mathcal{L}_{\inf}(p \rightarrow q) \rightarrow (\mathcal{L}_{\inf} p \rightarrow \mathcal{L}_{\inf} q)) \\
L4 &:= \Box(\mathcal{L}_{\sup}(p \rightarrow q) \rightarrow (\mathcal{L}_{\sup} p \rightarrow \mathcal{L}_{\sup} q)) \\
L5 &:= \Box(\mathcal{L}_{\inf} p \rightarrow \mathcal{N} p) \\
L6 &:= \Box(\mathcal{L}_{\sup} p \rightarrow \mathcal{N} p) \\
L7 &:= \Box(\mathcal{N} p \rightarrow p)
\end{aligned}\]

\subsection{Definitions}\label{definitions}

\[\begin{aligned}
T &:= \{ x \mid U < x < S \} \\
U &:= \mathcal{L}_{\inf} T \\
S &:= \mathcal{L}_{\sup} T \\
Tr &:= U \land T \land S
\end{aligned}\]

\section{Appendix B: Comparison of
Definitions}\label{appendix-b-comparison-of-definitions}

\begin{longtable}[]{@{}lll@{}}
\toprule\noalign{}
Aspect & Informal (modal5.md) & Formal (modal8.md) \\
\midrule\noalign{}
\endhead
\bottomrule\noalign{}
\endlastfoot
Language & Metric & Modal-logical \\
Basic concept & Number line & Neighborhood semantics \\
Limit & lim\_\{x→inf\} & L\_inf \\
Rigor & Intuitive & Formal \\
Trinity & Structure & Limit structure \\
\end{longtable}

\section{Afterword}\label{afterword}

You have read this treatise. Perhaps the refinement of the limit
definition surprised you. Perhaps the idea of topological modal logic
impressed you. Both are fine.

The investigation has shown: The Trinity was always thought as a limit
structure. The treatise refines this discourse, it does not replace it.
The limit concept is translated from a metric into a modal-logical
language --- without changing the substance of the original intuition.

What remains is the insight that the Trinity is \textbf{not an object}.
It is a \textbf{limit} --- what stands at the end of a sequence without
itself being an element of the sequence. It is the \textbf{structure} of
Totality itself.

One final question:

\begin{quote}
\textbf{Do we dare the leap into openness to the limit --- even though
the limit itself is not formally reachable, but only describable in the
language of topology?}
\end{quote}

\emph{This treatise was written in the spirit of rigorous modal logic,
yet in the language of philosophy -- for truth requires both: the
precision of the formula and the breadth of the concept.}

\end{document}
