PRP0056canonicalv1Functions as Tau-Objects
Functions as Tau-Objects
Payload
Functions as Tau-Objects
Functions as Tau-Objects
Functions as Tau-Objects
Summary
Functions as Tau-Objects
Statement
%
\label{prop:functions-as-objects}
The Pre-Yoneda embedding $y$
preserves the following structures:
\begin{enumerate}
\item[\textup{(i)}]
\textbf{Bipolar decomposition.}
For every $f \in \mathrm{Hol}_\tau(\tau^3, H_\tau)$:
\[
y(f)
\;=\;
e_+ \cdot y(f_+)
\;+\;
e_- \cdot y(f_-),
\]
where $f = e_+ \cdot f_+ + e_- \cdot f_-$
is the Idempotent Decomposition
\textup{(II.L07, Chapter~\ref{ch:idempotent-decomposition})}.
\item[\textup{(ii)}]
\textbf{Regularity.}
A holomorphic function $f$ is $\tau$-regular
at a point $p \in \tau^3$
\textup{(Definition~\ref{def:tau-regularity}, II.D49,
Chapter~\ref{ch:regularity-positive})}
if and only if $y(f)$ stabilizes at~$p$:
the $\omega$-germ $y(f)$
has a well-defined limiting value
at the point~$p$
in the profinite topology.
\item[\textup{(iii)}]
\textbf{ABCD coordinates.}
The image $y(f)$ inherits all four
ABCD coordinates from $f$:
the address data (A),
the B-channel exponent data,
the C-channel tetration data,
and the depth data (D).
A holomorphic function \textbf{has a position}
in~$\tau^3$.
\end{enumerate}
Proof / Justification
\emph{Clause~(i): Bipolar decomposition.}
Let $f \in \mathrm{Hol}_\tau(\tau^3, H_\tau)$.
By the Idempotent Decomposition Lemma (II.L07),
$f = e_+ \cdot f_+ + e_- \cdot f_-$,
where $f_\pm = e_\pm \cdot f$
are themselves $\tau$-holomorphic.
The $\omega$-germ transformer respects this decomposition:
at each stage~$k$,
\[
(G_f)_k
\;=\;
e_+ \cdot (G_{f_+})_k
\;+\;
e_- \cdot (G_{f_-})_k,
\]
because the idempotent projection
commutes with the stage-$k$ evaluation
(the idempotents $e_\pm$ are elements of $H_\tau$,
which is the codomain at every stage).
Passing to $\omega$-germ equivalence classes:
\[
[G_f]
\;=\;
e_+ \cdot [G_{f_+}]
\;+\;
e_- \cdot [G_{f_-}],
\]
which is $y(f) = e_+ \cdot y(f_+) + e_- \cdot y(f_-)$.
\smallskip
\emph{Clause~(ii): Regularity.}
By the positive regularity definition
(II.D49, Chapter~\ref{ch:regularity-positive}),
$f$ is $\tau$-regular at~$p$
if and only if the stage-$k$ values $f_k(p_k)$
stabilize: there exists $N$ such that
$f_k(p_k) = f_\ell(p_\ell)$
under the natural identification
for all $k, \ell \geq N$.
But the stage-$k$ values of $f$ at~$p$
are exactly the stage-$k$ values
of the $\omega$-germ transformer $G_f$ evaluated at~$p$.
Therefore $f$ is regular at~$p$
if and only if the $\omega$-germ $[G_f] = y(f)$
stabilizes at~$p$.
The regularity criterion (II.T34,
Chapter~\ref{ch:regularity-positive})
gives the equivalence explicitly:
$f$ is regular $\Leftrightarrow$
$f$ has a canonical extension to the interior
$\Leftrightarrow$ $y(f)$
has a well-defined profinite limit at~$p$.
\smallskip
\emph{Clause~(iii): ABCD coordinates.}
The ABCD structure is inherited stagewise.
The A-coordinate (address) of $y(f)$
is the address of the stabilization point
of the $\omega$-germ:
the profinite limit of the tower-coherent sequence
$(G_f)_k$.
The B-coordinate (exponent channel)
is $e_+ \cdot y(f)$;
the C-coordinate (tetration channel)
is $e_- \cdot y(f)$;
and the D-coordinate (depth)
is the stabilization stage---the
smallest $N$ such that
the $\omega$-germ has stopped acquiring
new spectral components.
Each coordinate is well-defined
because $f$ is $\tau$-holomorphic
and therefore satisfies tower coherence
and finite spectral support
(II.T32, Chapter~\ref{ch:sheaf-coherence}).
Source Context
- Registry source:
book-02.jsonlline 119 - Manuscript source:
2nd-edition/book-ii-categorical-holomorphy/02_mainmatter/part07/ch40-pre-yoneda.texlines 299-342
Lean / Formalization Notes
- Formalization:
formalized - Module:
TauLib.BookII.Regularity.PreYoneda - Name:
preyoneda_bipolar_check
Dependencies
- Canonical: II.D50, II.L07, II.T34, II.D49
Related Results
Generated by later projection phases.
Related Publications
Generated by later projection phases.
Revision Notes
- 2026-04-24: Initial pilot migration.
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