\documentclass[11pt,notitlepage,a4paper]{article}
\def\bare{n}
\usepackage[all]{xy}
\usepackage[english,greek]{babel}
\usepackage{dbnsymb, amsmath, graphicx, amssymb, datetime, multicol,
  stmaryrd, pifont, amscd, colortbl, mathtools, wasysym, needspace,
  import, longtable, overpic, enumitem, bbm, pdfpages, ../picins}
\usepackage{tensor}
\usepackage{txfonts}	% For \coloneqq; but harms \calA.
%\usepackage{mathtools}	% For \coloneqq.
%\usepackage{mathbbol}	% For \bbe; sometimes harmed by later packages.
\usepackage[usenames,dvipsnames]{xcolor}
\usepackage[textwidth=210mm,textheight=297mm,centering]{geometry}
\parindent 0in

% Following http://tex.stackexchange.com/a/847/22475:
\usepackage[setpagesize=false]{hyperref}
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}

% Following http://tex.stackexchange.com/questions/59340/how-to-highlight-an-entire-paragraph
\usepackage[framemethod=tikz]{mdframed}

\usepackage[T1]{fontenc}

\def\myurl{http://www.math.toronto.edu/~drorbn}
\def\thistalk{Matemale-1804}
\def\title{Solvable Approximations of the Quantum $sl_2$ Portfolio}

\def\navigator{{
  \href{\myurl}{Dror Bar-Natan}:
  \href{\myurl/Talks}{Talks}:
  \href{\myurl/Talks/\thistalk/}{\thistalk}:
}}
\def\webdef{{{\greektext web}$\coloneqq$\href{http://drorbn.net/mm18}{http://drorbn.net/mm18/}}}
\def\web#1{{\href{\myurl/Talks/\thistalk/#1}{{\greektext web}/#1}}}
\def\titleA{{\bf\title}}
\def\titleB{{\title}}
\def\titleC{{\title}}

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\def\imagetop#1{\vtop{\null\hbox{#1}}}

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\def\arXiv#1{{\href{http://front.math.ucdavis.edu/#1}{arXiv:\linebreak[0]#1}}}

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\def\AS{\mathit{AS}}
\def\bbZZ{{\mathbb Z\mathbb Z}}
\def\ced{{\linebreak[1]\null\hfill\text{$\bigcirc$}}}
\def\CW{\text{\it CW}}
\def\diag{\operatorname{diag}}
\def\FL{\text{\it FL}}
\def\Hom{\operatorname{Hom}}
\def\IHX{\mathit{IHX}}
\def\mor{\operatorname{mor}}
\def\PvT{{\mathit P\!v\!T}}
\def\qed{{\linebreak[1]\null\hfill\text{$\Box$}}}
\def\remove{\!\setminus\!}
\def\STU{\mathit{STU}}
\def\SW{\text{\it SW}}
\def\TC{\mathit{TC}}
\def\tr{\operatorname{tr}}
\def\vT{{\mathit v\!T}}

\def\barT{{\bar T}}
\def\bbe{\mathbbm{e}}
\def\bbD{{\mathbb D}}
\def\bbE{{\mathbb E}}
\def\bbO{{\mathbb O}}
\def\bbQ{{\mathbb Q}}
\def\bbR{{\mathbb R}}
\def\bbT{{\mathbb T}}
\def\bbZ{{\mathbb Z}}
\def\bcA{{\bar{\mathcal A}}}
\def\calA{{\mathcal A}}
\def\calD{{\mathcal D}}
\def\calF{{\mathcal F}}
\def\calG{{\mathcal G}}
\def\calI{{\mathcal I}}
\def\calK{{\mathcal K}}
\def\calO{{\mathcal O}}
\def\calP{{\mathcal P}}
\def\calR{{\mathcal R}}
\def\calS{{\mathcal S}}
\def\calT{{\mathcal T}}
\def\calU{{\mathcal U}}
\def\fraka{{\mathfrak a}}
\def\frakb{{\mathfrak b}}
\def\frakg{{\mathfrak g}}
\def\frakh{{\mathfrak h}}
\def\tilE{\tilde{E}}
\def\tilq{{\tilde{q}}}

\def\tDelta{\tensor[^t]{\Delta}{}}
\def\tf{\tensor[^t]{f}{}}
\def\tF{\tensor[^t]{F}{}}
\def\tg{\tensor[^t]{g}{}}
\def\tI{\tensor[^t]{I}{}}
\def\tm{\tensor[^t]{m}{}}
\def\tR{\tensor[^t]{R}{}}
\def\tsigma{\tensor[^t]{\sigma}{}}
\def\tS{\tensor[^t]{S}{}}
\def\tSW{\tensor[^t]{\SW}{}}

% From http://tex.stackexchange.com/questions/154672/how-to-get-a-medium-sized-otimes
\DeclareMathOperator*{\midotimes}{\text{\raisebox{0.25ex}{\scalebox{0.8}{$\bigotimes$}}}}

%%%

\def\credits{With \href{http://www.rolandvdv.nl/}{Roland van der Veen}}

\def\Main{{\raisebox{2mm}{\parbox[t]{3.96in}{
{\red\bf Our Main Theorem} (loosely stated). Everything that matters
in the quantum $sl_2$ portfolio can be continuously expressed in terms of docile
perturbed Gaussians using solvable approximations.~\ced

{\red\bf Our Main Points.}
\begin{itemize}[leftmargin=*,labelindent=0pt,itemsep=-2pt,topsep=0pt]
\item What's the ``quantum $sl_2$ portfolio''?
\item What in it ``matters'' and why?\hfill\text{\blue\small(the most important question)}
\item What's ``solvable approximation''? What's ``continuously''?
\item What are ``docile perturbed Gaussians''?
\item Why do they matter?\hfill\text{\blue\small($2^{nd}$ most important)}
\item How proven?\hfill\text{\blue\small(docile)}
\item How implemented?\hfill\text{\blue\small(sacred; the work of unsung heroes)}
\item Some context and background.
\item What's next?
\end{itemize}
}}}}

\def\Portfolio{{\raisebox{4mm}{\parbox[t]{3.96in}{
\parpic[r]{$\xymatrix@C=12mm{
  R,s\in \{QU^{\otimes S}\}
    \ar@`{p+(12,12),p+(-12,12)}_{\otimes,m^{ij}_k,\Delta^i_{jk},S_i,\theta}
    \ar[r]^<>(0.5){A\bbD,\,S\bbD}
  & \{CU^{\otimes S}\}
    \ar@`{p+(12,12),p+(-12,12)}_{\otimes,m^{ij}_k,\Delta^i_{jk},S_i,\theta}
}$}
{\red\bf The quantum $sl_2$ Portfolio} includes a classical universal enveloping algebra $CU$,
its quantization $QU$, their tensor powers $CU^{\otimes S}$ and $QU^{\otimes S}$ with the ``tensor
operations'' $\otimes$, their products $m^{ij}_k$, coproducts $\Delta^i_{jk}$ and antipodes $S_i$,
their Cartan automophisms $C\theta\colon CU\to CU$ and $Q\theta\colon QU\to QU$, the
``dequantizators'' $A\bbD\colon QU\to CU$ and $S\bbD\colon QU\to CU$, and most importantly, the
$R$-matrix $R$ and the Drinfel'd element $s$. All this in any PBW basis, and change of basis maps
are included.
}}}}

\def\SolvableApproximation{{\raisebox{2mm}{\parbox[t]{3.96in}{
{\red\bf Solvable Approximation.} A quantized universal enveloping algebra (aka ``quantum group'') is an
$\infty$-dimensional inverse limit.
%\[ \xymatrix{
%  \text{untrimmed} \ar[r] &
%  \text{half-trimmed} \ar[r] &
%  \text{fully-trimmed} \\
%  \text{unmanageable} &
%  \text{``solvable approximation''} &
%  \text{``finite-type''}
%} \]
}}}}

\def\bracket{$b({\red\uppertriang})=b\colon{\red\uppertriang}\otimes\!{\red\uppertriang}
  \to{\red\uppertriang}$}
\def\cobracket{$b({\blue\lowertriang})\leadsto\delta\colon{\red\uppertriang}
  \to{\red\uppertriang}\otimes\!{\red\uppertriang}$}

\def\Recomposing{{\raisebox{3mm}{\parbox[t]{3.95in}{
{\red\bf Recomposing $gl_n$.} Half is enough! $gl_n\oplus\fraka_n = \calD(\uppertriang,b,\delta)$:
\vskip 14mm
Now define $gl^\epsilon_n\coloneqq\calD(\uppertriang,b,\epsilon\delta)$. Schematically, this is
$[\uppertriang,\uppertriang]=\uppertriang$, $[\lowertriang,\lowertriang]=\epsilon\lowertriang$,
and $[\uppertriang,\lowertriang]=\lowertriang+\epsilon\uppertriang$. In detail, it is
}}}}

\def\glne{{\raisebox{0mm}{\parbox[t]{3.0625in}{
$[e_{ij},e_{kl}]\!=\!\delta_{jk}e_{il}-\delta_{li}e_{kj}$
  \hfill$[f_{ij},f_{kl}]\!=\!\epsilon\delta_{jk}f_{il}-\epsilon\delta_{li}f_{kj}$
\newline
$[e_{ij},f_{kl}] \!=\!
  \delta_{jk}(\epsilon\delta_{j<k}e_{il}+\delta_{il}(h_i+\epsilon g_i)/2+\delta_{i>l}f_{il})$
\newline\null\hfill
  $-\delta_{li}(\epsilon\delta_{k<j}e_{kj}+\delta_{kj}(h_j+\epsilon g_j)/2+\delta_{k>j}f_{kj})$
\newline$[g_i,e_{jk}] \!=\! (\delta_{ij}-\delta_{ik})e_{jk}$
  \hfill$[h_i,e_{jk}] \!=\! \epsilon(\delta_{ij}-\delta_{ik})e_{jk}$
\newline$[g_i,f_{jk}] \!=\! (\delta_{ij}-\delta_{ik})f_{jk}$
  \hfill$[h_i,f_{jk}] \!=\! \epsilon(\delta_{ij}-\delta_{ik})f_{jk}$
}}}}

\def\SolvApp{{\raisebox{2mm}{\parbox[t]{3.95in}{
{\red\bf Solvable Approximation (2).} At $\epsilon=1$ and modulo $h=g$, the
above is just $gl_n$. By rescaling at $\epsilon\neq 0$, $gl_n^\epsilon$ is
independent of $\epsilon$. We let $gl_n^k$ be $gl_n^\epsilon$ regarded as
an algebra over $\bbQ[\epsilon]/\epsilon^{k+1}=0$. It is the ``$k$-smidgen
solvable approximation'' of $gl_n$!

Recall that $\frakg$ is ``solvable'' if iterated commutators in it ultimately vanish:
$\frakg_2\coloneqq[\frakg,\frakg],\ \frakg_3\coloneqq[\frakg_2,\frakg_2],\ \ldots,\ \frakg_d=0$.
Equivalently, if it is a subalgebra of some large-size $\uppertriang$ algebra.

{\red Note.} This whole process makes sense for arbitrary semi-simple Lie algebras.
}}}}

\def\Docile{{\raisebox{2mm}{\parbox[t]{3.95in}{
\parshape 5 0in 2.25in 0in 2.25in 0in 2.25in 0in 2.25in 0in 3.95in
{\red\bf Definition.} A ``docile perturbed Gaussian'' in the variables $(z_i)_{i\in
S}$ \text{over} the ring $R$ is an expression of the form
\[
  \bbe^{q^{ij}z_iz_j}P
  = \bbe^{q^{ij}z_iz_j}\left(\sum_{k\geq 0}\epsilon^kP_k\right),
\]
where all coefficients are in $R$ and where $P$ is a ``docile series'': $\deg
P_k\leq 4k$.

{\red Docililty Matters!} The rank of the space of docile series to $\epsilon^k$
is polynomial in the number of variables $|S|$.
}}}}

\def\Faddeev{{\raisebox{2mm}{\parbox[t]{3.96in}{
\parshape 5 0in 2.5in 0in 2.5in 0in 2.5in 0in 2.5in 0in 3.96in
{\red\bf Faddeev's Formula} (In as much as \text{we} can tell, first
appeared w/o proof in Faddeev~\cite{Faddeev:ModularDouble},
rediscovered and proven in Quesne~\cite{Quesne:Jackson}, and
again with easier proof, in Zagier~\cite{Zagier:Dilogarithm}).
With ${[n]_q\coloneqq\frac{q^n-1}{q-1}}$, with
$[n]_q!\coloneqq[1]_q[2]_q\cdots[n]_q$ and with
$\bbe_q^x\coloneqq\sum_{n\geq 0}\frac{x^n}{[n]_q!}$, we have

\[ \log\bbe_q^x = \sum_{k\geq 1}\frac{(1-q)^kx^k}{k(1-q^k)}
  = x + \frac{(1-q)^2x^2}{2(1-q^2)} + \ldots .
\]

{\red Proof.} We have that $\bbe_q^x = \frac{\bbe_q^{qx}-\bbe_q^x}{qx-x}$ (``the $q$-derivative of
$\bbe_q^x$ is itself''), and hence $\bbe_q^{qx} = (1+(1-q)x)\bbe_q^x$, and
\[ \log\bbe_q^{qx} = \log(1+(1-q)x) + \log\bbe_q^x. \]
Writing $\log\bbe_q^x=\sum_{k\geq 1}a_kx^k$ and comparing powers of $x$, we get
$q^ka_k=-(1-q)^k/k+a_k$, or $a_k=\frac{(1-q)^k}{k(1-q^k)}$. \qed
}}}}

\def\MetaAssoc{{\parbox{1.1in}{
  (meta-associativity: $m^{ab}_x\act m^{xc}_y=m^{bc}_x\act m^{ax}_y$)
  \newline
  (tangles are generated by $\overcrossing$ and $\undercrossing$)
}}}

\def\Genus{{\raisebox{2mm}{\parbox[t]{2.96in}{
{\red\bf Genus.} Every knot is the boundary of an orientable ``Seifert
Surface'' (\web{SS}), and the least of their genera is the ``genus''
of the knot.

{\red Claim.} The knots of genus $\leq 2$ are precisely the images of 4-component tangles via
}}}}

\def\Ribbon{{\raisebox{2mm}{\parbox[t]{3.96in}{
{\red\bf A Bit about Ribbon Knots.} A ``ribbon knot'' is a knot that can be
presented as the boundary of a disk that has ``ribbon singularities'', but
no ``clasp singularities''. A ``slice knot'' is a knot in $S^3=\partial
B^4$ which is the boundary of a non-singular disk in $B^4$. Every ribbon
knots is clearly slice, yet,

{\red Conjecture.} Some slice knots are not ribbon.

{\red Fox-Milnor.} The Alexander polynomial of a ribbon knot is always of
the form $A(t)=f(t)f(1/t)$.\hfill{(also~for~slice)}
}}}}

\def\GST{\parbox{0.5in}{\tiny
  Gompf, Scharlemann, Thompson
  \cite{GompfScharlemannThompson:Counterexample}
}}

\def\Ta{$\calT_{2n}$}
\def\Tb{$U\in\calT_n$}
\def\Tc{ribbon $K\in\calT_1$}
\def\Aa{$\calA_{2n}$}
\def\Ab{$1\in\calA_n$}
\def\Ac{$z(K)\in\calR\subseteq\calA_1$}
\def\Ra{with $\calR\coloneqq$}
\def\Rb{$\kappa(\tau^{-1}(1))$}

\def\Gold{{\raisebox{5mm}{\begin{minipage}[t]{3.95in}
\pichskip{0mm}\parpic[l]{
  \includegraphics[height=0.4in]{../Greece-1607/IASLogo.png}
} \picskip{2}
{\red\bf The Gold Standard} is set by the ``$\Gamma$-calculus'' Alexander formulas
\cite{Bar-NatanSelmani:MetaMonoids, KBH}. An $S$-component
tangle $T$ has $\Gamma(T) \in R_S\times M_{S\times S}(R_S) =
\left\{\begin{array}{c|c}\omega&S\\\hline S&A\end{array}\right\}$ with
$R_S\coloneqq\bbZ(\{t_a\colon a\in S\})$:

$\displaystyle
  \left(\tensor[_a]{\overcrossing}{_b},\tensor[_b]{\undercrossing}{_a}\right)
  \to
  \begin{array}{c|cc} 1 & a & b \\ \hline a & 1 & 1-t_a^{\pm 1} \\ b & 0 &
t_a^{\pm 1} \end{array}
$
\hfill$\displaystyle
  T_1\sqcup T_2
  \to
  \begin{array}{c|cc} \omega_1\omega_2 & S_1 & S_2 \\ \hline S_1 & A_1 & 0
\\ S_2 & 0 & A_2 \end{array}
$
\vskip -1mm
\[ \begin{CD}
  \begin{array}{c|ccc}
    \omega & a & b & S \\
    \hline
    a & \alpha & \beta & \theta \\
    b & \gamma & \delta & \epsilon \\
    S & \phi & \psi & \Xi
  \end{array}
  @>{\displaystyle m^{ab}_c}>{\displaystyle t_a,t_b\to t_c}>
  \left(\!\begin{array}{c|cc}
    (1-\beta)\omega & c & S \\
    \hline
    c & \gamma+\frac{\alpha\delta}{1-\beta} & \epsilon+\frac{\delta\theta}{1-\beta} \\
    S & \phi+\frac{\alpha\psi}{1-\beta} & \Xi+\frac{\psi\theta}{1-\beta}
  \end{array}\!\right)
\end{CD} \]
{\footnotesize (Roland: ``add to $A$ the product of column $b$ and row
$a$, divide by $(1-A_{ab})$, delete column $b$ and row $a$''.)}

\vskip 1mm
\parshape 1 0in 3.45in
For long knots, $\omega$ is Alexander, and that's the fastest \text{Alexander}
algorithm I know!
\hfill\text{\footnotesize Dunfield: 1000-crossing fast.}

\vskip 1.5mm

\resizebox{\linewidth}{!}{$\displaystyle
  \begin{CD}
    \begin{array}{c|cc}
      \omega & a & S \\
      \hline
      a & \alpha & \theta \\
      S & \phi & \Xi
    \end{array}
    @>q\Delta^a_{bc}>{\mu\coloneqq T_a-1\atop{\nu\coloneqq \alpha-\sigma_a\atop T_a\mapsto T_bT_c}}>
    \left(\begin{array}{c|ccc}
      \omega & b & c & S \\
      \hline
      b &
        (\sigma_a-\alpha T_a-\nu T_c)/\mu &
        (T_b-1)T_c\nu/\mu &
        (T_b-1)T_c\theta/\mu \\
      c &
        (T_c-1)\nu/\mu &
        (\alpha-\sigma_a T_a-\nu T_c)/\mu &
        (T_c-1)\theta/\mu \\
      S & \phi & \phi & \Xi
    \end{array}\right)
    \\
    @VdS^aVT_a\to T_a^{-1}V \\
    \hspace{0mm}\left(\begin{array}{c|cc}
      \alpha\omega/\sigma_a & a & S \\
      \hline
      a & 1/\alpha & \theta/\alpha \\
      S & -\phi/\alpha & (\alpha\Xi-\phi\theta)/\alpha
    \end{array}\right)\hspace{-33mm}
    @.
    \raisebox{-2mm}{\hspace{16mm}\parbox{81mm}{
      Where $\sigma$ assigns to every $a\in S$ a Laurent
      monomial $\sigma_a$ in $\{t_b\}_{b\in S}$ subject to
      $\sigma\left(
        \tensor[_a]{\overcrossing}{_b},\tensor[_b]{\undercrossing}{_a}
      \right) = (a\to1,\,b\to t_a^{\pm 1})$,
      $\sigma(T_1\sqcup T_2)=\sigma(T_1)\sqcup\sigma(T_2)$, 
      and $\sigma\act m^{ab}_c =
      \left.
        (\sigma\setminus\{a,b\})\cup(c\to\sigma_a\sigma_b)
      \right|_{t_a,t_b\to t_c}$.
    }}
  \end{CD}
$}
\end{minipage}}}}

\def\Vo{{\raisebox{2mm}{\parbox[t]{3.5in}{
{\red\bf Vo's Thesis \cite{Vo:Thesis}.} A proof of the Fox-Milnor theorem
for ribbon knots using this technology (and more).
}}}}

\def\Implementation{{\raisebox{2.5mm}{\parbox[t]{2in}{
\parshape 2 0in 2in 0.1in 1.5in
{\red\bf Implementation} key idea:
\newline $\left(\omega,A=(\alpha_{ab})\right)\leftrightarrow$
\newline $\left(\omega,\lambda=\sum\alpha_{ab}t_ah_b\right)$
}}}}

\def\technique{{\raisebox{2mm}{\parbox[t]{2.75in}{
{\red\bf The Yang-Baxter Technique.} Given an algebra $U$ (typically
$\hat\calU(\frakg)$ or $\hat\calU_q(\frakg)$) and elements
\[ R=\sum a_i\otimes b_i\in U\otimes U \quad\text{and}\quad C\in U, \]
form \hfill $\displaystyle Z=\sum_{i,j,k}Ca_ib_ja_kC^2b_ia_jb_kC.$\hfill\null

{\red Problem.} Extract information from $Z$.

{\red The Dogma.} Use representation theory. In principle finite, but {\em
slow}.
}}}}

\def\Moduli{{\raisebox{2mm}{\parbox[t]{1.95in}{
{\red\bf The (fake) moduli} of Lie algebras on $V$, a quadratic variety in
$(V^\ast)^{\otimes 2}\otimes V$ is on the right. We care about $sl_{17}^k
\coloneqq sl_{17}^\epsilon/(\epsilon^{k+1}=0)$.
}}}}

\def\mmr{{\raisebox{2mm}{\parbox[t]{3.95in}{
\parshape 3 0in 2.45in 0in 2.45in 0in 3.95in
{\red\bf Theorem} (\cite{Bar-NatanGaroufalidis:MMR}, conjectured~\cite{MM},
elucidated~\cite{Ro}). Let
$J_d(K)$ be the coloured Jones polynomial of $K$, in
the $d$-dimensional representation of $sl_2$. Writing
\[ \left.
  \frac{(q^{1/2}-q^{-1/2})J_d(K)}{q^{d/2}-q^{-d/2}}
  \right|_{q=e^\hbar} =
  \sum_{j,m\geq 0} a_{jm}(K)d^j\hbar^m,
\]

\parshape 5 0in 3in 0in 3in 0in 3in 0in 3in 0in 3.95in
``below diagonal'' coefficients vanish, $a_{jm}(K)=0$ if $j>m$, and
``on diagonal'' coefficients give the inverse of the
Alexander polynomial:
$\left(\sum_{m=0}^\infty a_{mm}(K)\hbar^m\right)\cdot \omega(K)(e^\hbar)=1$.

``Above diagonal'' we have {\red Rozansky's Theorem}
\cite[(1.2)]{Rozansky:U1RCC}:
\[ J_d(K)(q) = \frac{q^d-q^{-d}}{(q-q^{-1})\omega(K)(q^d)}
  \left(1+
    \sum_{k=1}^\infty \frac{(q-1)^k\rho_k(K)(q^d)}{\omega^{2k}(K)(q^d)}
  \right).
\]

\parshape 1 0in 2.5in
{\red Prior art.} Some amazing computations by Rozansky and Overbay in
\cite{Rozansky:Burau, Rozansky:U1RCC} and in \cite{Overbay:Thesis}.
}}}}

\def\MMG{\parbox{0.6in}{\scriptsize\raggedright
  Melvin, Morton, Garoufalidis
}}

\pagestyle{empty}

\begin{document} \latintext
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\vspace{-7mm}
\begin{multicols}{2} \raggedcolumns

{\red\bf $\calG\calD\calO$-Categories.} Given $\frakg$ with basis
$B=\{x,y,\ldots\}$, consider the following diagram:
\[ \xymatrix@C=11.5mm{
  \bbQ=\hat\calU_{(q)}\left(\bigoplus_0\frakg\right)
    \ar[r]^<>(0.5)Z &
  \hat\calU_{(q)}\left(\frakg\right)
    \ar@/^/[r]^<>(0.5)\Delta &
  \hat\calU_{(q)}\left(\bigoplus_2\frakg\right)
    \ar@/^/[l]^<>(0.5)m \\
  \hat\calS\left(\emptyset\right)
    \ar[r]^<>(0.5)Z
    \ar[u] &
  \hat\calS\left(B\right)
    \ar@/^/[r]^<>(0.5)\Delta
    \ar@/^/[u]^{\bbO(xy\ldots\colon\cdot)}
    \ar@/_/[u]_{\bbO(yx\ldots\colon\cdot)}
    \ar@`{p+(-16,-16),p+(+16,-16)}^{\SW_{xy}} &
  \hat\calS\left(B_1,B_2\right)
    \ar@/^/[l]^<>(0.5)m
    \ar[u]_{\bbO(y_1x_1\ldots\otimes y_2x_2\ldots\colon\cdot)}
} \]
Hence $Z$, $\SW_{xy}$, $m$, $\Delta$, (and likewise $S$ and $\theta$) are
morphisms in the {\em completion} of the monoidal category $\calF$ whose objects
are finite sets $B$ and whose morphisms are $\mor_\calF(B,B') \coloneqq
\Hom_\bbQ\left(\calS(B)\to\calS(B')\right) = \calS\left(B^\ast,B'\right)$ (by
convention, $x^\ast=\xi$, $y^\ast=\eta$, etc.). Ergo we need to {\em
consolidate} (at least parts of) said completion.

{\red\bf Aside.} ``Consolidate'' means  ``give a finite name to an infinite object,
and figure out how to sufficiently manipulate such finite names''. E.g., solving
$f''=-f$ we encounter and set $\sum\frac{(-1)^kx^{2k}}{(2k)!}\leadsto\cos x$,
$\sum\frac{(-1)^kx^{2k+1}}{(2k+1)!}\leadsto\sin x$, and then $\cos^2x+\sin^2x=1$
and $\sin(x+y)=\sin x\cos y+\cos x\sin y$.

{\red\bf The Composition Law.} If 
\[ \begin{CD}
  \calS(B_0) @>f>\tf\in\bbQ\llbracket\zeta_{0i},z_{1j}\rrbracket>
  \calS(B_1) @>g>\tg\in\bbQ\llbracket\zeta_{1j},z_{2k}\rrbracket>
  \calS(B_2)
\end{CD} \]
then $\tensor[^t]{(f\act g)}{} = \tensor[^t]{(g\circ f)}{} =
\left(\left.g\right|_{\zeta_{1j}\to\partial_{z_{1j}}}f\right)_{z_{1j}=0}$.

{\red\bf Examples.}

\begin{enumerate}[leftmargin=*,labelindent=0pt,itemsep=-2pt,topsep=0pt]

\item The $1$-variable identity map $I\colon\calS(z)\to\calS(z)$
is given by $\tI_1 = \yellowm{\bbe^{z\zeta}}$ and the $n$-variable one by
$\tI_n = \yellowm{\bbe^{z_1\zeta_1+\dots+z_n\zeta_n}}$.

\needspace{9mm}
\item The ``$z_i\to z_j$ variable rename map
$\sigma^i_j\colon\calS(z_i)\to\calS(z_j)$ becomes $\tsigma^i_j =
\yellowm{\bbe^{z_j\zeta_i}}$, and it's easy to rename several variables
simultaneously.

\item The ``archetypal multiplication map
$m^{ij}_k\colon\calS(z_i,z_j)\to\calS(z_k)$'' has
$\tm = \yellowm{\bbe^{z_k(\zeta_i+\zeta_j)}}$.

\item The ``archetypal coproduct
$\Delta^i_{jk}\colon\calS(z_i)\to\calS(z_j,z_k)$'', given by $z_i\to
z_j+z_k$ or $\Delta z = z\otimes 1+1\otimes z$, has $\tDelta =
\yellowm{\bbe^{(z_j+z_k)\zeta_i}}$.

\item $R$-matrices tend to have terms of the form $\bbe_q^{\hbar
y_1x_2} \in \calU_q\otimes\calU_q$. The ``baby $R$-matrix'' is
$\tR = \yellowm{\bbe^{\hbar yx}\in\calS(y,x)}$.

\end{enumerate}

{\red\bf Proposition.} If $F\colon\calS(B)\to\calS(B')$ is linear and
``continuous'', then $\tF=\exp\left(\sum_{z_i\in
B}\zeta_iz_i\right)\act F$.

{\red\bf The Heisenberg Example.} The ``Weyl form of the canonical commutation
relations'' states that if $[y,x]=t$ and $t$ is central, then $\bbe^{\xi
x}\bbe^{\eta y} = \bbe^{\eta y}\bbe^{\xi x}\bbe^{-\eta\xi t}$. Thus with
\[ \xymatrix{
  \calS(t,y,x)
    \ar@/^/[r]^{\bbO_{xy}}
    \ar@/_/[r]_{\bbO_{yx}}
    \ar@`{p+(-16,+16),p+(-16,-16)}_{\SW_{xy}} &
  \calU(t,y,x)
} \]
we have $\tSW_{xy} = \yellowm{\bbe^{\tau t+\eta y+\xi x-\eta\xi t}}$.

\parpic[r]{\input{figs/Zipping.pdf_t}}
{\red\bf The Zipping Issue} (between unbound and bound lies half-zipped).

{\red\bf Zipping.} If $P(\zeta^j,z_i)$ is a polynomial, or whenever otherwise
convergent, set
\[ \left\langle P(\zeta^j,z_i)\right\rangle_{(\zeta^j)} =
  \left.P\left(\partial_{\!z_j},z_i\right)\right|_{z_i=0}.
\]
(E.g., if $P=\sum a_{nm}\zeta^nz^m$ then $\langle P\rangle_\zeta = \sum
n!a_{nn}$).

\needspace{15mm}
{\red\bf The Zipping / Contraction Theorem.} If $P$ has a finite
$\zeta$-degree and the $y$'s and the $q$'s are ``small'' then
\[ \left\langle
P(z_i,\zeta^j)\bbe^{\eta^iz_i+y_j\zeta^j}\right\rangle_{(\zeta^j)}
  = \left\langle
P(z_i+y_i,\zeta^j)\bbe^{\eta^i(z_i+y_i)}\right\rangle_{(\zeta^j)},
\]
(proof: replace $y_j\to\hbar y_j$ and test at $\hbar=0$ and at
$\partial_\hbar$), and
\begin{multline*}
  \left\langle
P(z_i,\zeta^j)\bbe^{c+\eta^iz_i+y_j\zeta^j+q^i_jz_i\zeta^j}\right\rangle_{(\zeta^j)}
\\
  = \det(\tilq)\left\langle
    P(\tilq_i^k(z_k+y_k),\zeta^j)\bbe^{c+\eta^i\tilq^k_i(z_k+y_k)}
  \right\rangle_{(\zeta^j)}
\end{multline*}
where $\tilq$ is the inverse matrix of $1-q$:
$(\delta^i_j-q^i_j)\tilq^j_k=\delta^i_k$
(proof: replace $q^i_j\to\hbar q^i_j$ and test at $\hbar=0$ and at
$\partial_\hbar$).

{\red\bf Implementation.}\hfill\web{ZipBindDemo}

\def\cellscale{0.645}
\newcount\snip
\snip=1\loop
  \par\includegraphics[scale=\cellscale]{Snips/ZipBindDemo-\the\snip.pdf}
  \advance \snip 1
\ifnum \snip<23 \repeat

{\red\bf The 2D Lie Algebra.} Clever people know$^\ast$ that if $[a,x]
= \gamma x$ then $\bbe^{\xi x}\bbe^{\alpha a} = \bbe^{\alpha
a}\bbe^{\bbe^{-\gamma\alpha}\xi x}$. Ergo with
\[ \xymatrix{
  \calS(a,x)
    \ar@/^/[r]^{\bbO_{ax}}
    \ar@/_/[r]_{\bbO_{xa}}
    \ar@`{p+(-16,+16),p+(-16,-16)}_{\SW_{ax}} &
  \calU(a,x)
} \]
we have $\tSW_{ax} = \yellowm{\bbe^{\alpha a + \bbe^{-\gamma\alpha}\xi x}}$.

{\footnotesize $\ast$ Indeed $xa = (a-\gamma)x$
thus
$xa^n = (a-\gamma)^nx$ thus $x\bbe^{\alpha a} = \bbe^{\alpha(a-\gamma)}x
= \bbe^{-\gamma\alpha}\bbe^{\alpha a}x$ thus $x^n\bbe^{\alpha a} =
\bbe^{\alpha a}(\bbe^{-\gamma\alpha})^nx^n$ thus $\bbe^{\xi x}\bbe^{\alpha
a} = \bbe^{\alpha a}\bbe^{\bbe^{-\gamma\alpha}\xi x}$.}

{\red\bf The Real Thing.} In $QU/(\epsilon^2=0)$ over
$\bbQ\llbracket\hbar\rrbracket$ using the $yax$ order,
$T=\bbe^{\hbar t}$, $\barT=T^{-1}$,
$\calA=\bbe^{\gamma\alpha}$, and $\bcA=\calA^{-1}$, we have 
\[
  \tR_{ij} = \yellowm{\bbe^{\hbar(y_ix_j-t_ia_j/\gamma)}
  \left(1+\epsilon\hbar\left(
    a_ia_j/\gamma-\gamma\hbar^2y_i^2x_j^2/4
  \right)\right)}
\]
in $\calS(B_i,B_j)$, and in $\calS(B^\ast_1,B^\ast_2,B)$ we have
\[
  \tm \!=\! \yellowm{
    \bbe^{(\alpha _1+\alpha _2)a+\eta _2 \xi _1(1-T)/\hbar + (\xi_1\bcA_2 +
      \xi _2)x + (\eta_1+\eta_2\bcA_1) y} \left(1 \!+\! \epsilon\lambda_m\right)
  },
\]
where {\footnotesize$\lambda_m \!=\!
\yellowm{2a\eta_2\xi_1T
\!+\! \frac{1}{4}\gamma\eta_2^2\xi_1^2\left(3T^2\!-\!4T\!+\!1\right)/\hbar
\!-\! \frac{1}{2}\gamma\eta_2\xi_1^2(3T\!-\!1)x\bcA_2}$
$\yellowm{- \frac{1}{2}\gamma\eta_2^2\xi_1(3 T\!-\!1)y\bcA_1}
\yellowm{+ \gamma\eta_2\xi_1xy\hbar\bcA_1\bcA_2}$}.
Similar formulas delight us for $\tDelta$ and $\tS$.

{\red\bf A generic morphism.}
\[ \input{figs/GDOMorphism.pdf_t} \]

\end{multicols}

\vskip -3mm
{\red\bf Implementation.}\hfill\web{SL2Portfolio}

\vskip -5mm
\def\cellscale{0.45}
\begin{tabular}{ccc}
\includegraphics[scale=\cellscale]{figs/QZip.pdf} &
\includegraphics[scale=\cellscale]{figs/LZip.pdf} &
\includegraphics[scale=\cellscale]{figs/Bind.pdf}
\end{tabular}

\begin{multicols}{2}

{\red\bf A Partial To Do List.}
\begin{itemize}[leftmargin=*,labelindent=0pt,itemsep=-4pt,topsep=0pt]
\item Complete all ``docility'' arguments by identifying a ``contained'' docile
substructure.
\item Understand denominators and get rid of them.
\item See if much can be gained by including $P$ in the exponential:
$\bbe^{L+Q}P\leadsto\bbe^{L+Q+P}$?
\item Clean the program and make it efficient.
\item Run it for all small knots and links, at $k=2,3$.
\item Understand the centre and figure out how to read the output.
\item Execute the Drinfel'd double procedule at $\bbE$-level (and thus get rid of
\verb$DeclareAlgebra$ and all that is around it!).
\item Extend to $sl_3$ and beyond.
\item Do everything with \verb$Zip$ and \verb$Bind$ as the fundamentals,
  without ever referring back to (quantized) Lie algebras.
\item Prove a genus bound and a Seifert formula.
\item Obtain ``Gauss-Gassner formulas'' (\web{NCSU}).
\item Relate with Melvin-Morton-Rozansky and with Rozansky-Overbay.
\item Understand the braid group representations that arise.
\item Find a topological interpretation. The Garoufalidis-Rozansky
  ``loop expansion'' \cite{GaroufalidisRozansky:LoopExpansion}?
\item Figure out the action of the Cartan automorphism.
\item Disprove the ribbon-slice conjecture!
\item Figure out the action of the Weyl group.
\item Do everything at the ``arrow diagram'' level of finite-type invariants of
(rotational) virtual tangles.
\item What else can you do with the ``solvable approximations''?
\item And with the ``Gaussian zip and bind'' technology?
\end{itemize}

\end{multicols}\vspace{-6mm}\begin{multicols}{2}

{\red\bf References.}{\footnotesize
%\par\vspace{-3mm}
\renewcommand{\section}[2]{}%
\begin{thebibliography}{}
\setlength{\parskip}{0pt}
\setlength{\itemsep}{0pt plus 0.3ex}

\bibitem[BN1]{KBH} D.~Bar-Natan,
  {\em Balloons and Hoops and their Universal Finite Type Invariant, BF
    Theory, and an Ultimate Alexander Invariant,}
  \web{KBH}, \arXiv{1308.1721}.

\bibitem[BN2]{K17}  D.~Bar-Natan,
  {\em Polynomial Time Knot Polynomial,} research proposal for the 2017
  Killam Fellowship, \web{K17}.

\bibitem[BNG]{Bar-NatanGaroufalidis:MMR} D.~Bar-Natan and S.~Garoufalidis,
  {\em On the Melvin-Morton-Rozansky conjecture,}
  Invent.\ Math.\ {\bf 125} (1996) 103--133.

\bibitem[BNS]{Bar-NatanSelmani:MetaMonoids} D.~Bar-Natan and S.~Selmani,
  {\em Meta-Monoids, Meta-Bicrossed Products, and the Alexander
    Polynomial,}
  J.\ of Knot Theory and its Ramifications {\bf 22-10} (2013),
  \arXiv{1302.5689}.

\bibitem[BV]{PP1} D.~Bar-Natan and R.~van der Veen,
  {\em A Polynomial Time Knot Polynomial,}
  Proc.\ Amer.\ Math.\ Soc., to appear, \arXiv{1708.04853}.

\bibitem[Fa]{Faddeev:ModularDouble} L.~Faddeev,
  {\em Modular Double of a Quantum Group,}
  \arXiv{math/9912078}.

\bibitem[GR]{GaroufalidisRozansky:LoopExpansion} S.~Garoufalidis and L.~Rozansky,
  {\em The Loop Exapnsion of the Kontsevich Integral, the Null-Move, and $S$-Equivalence,}
  \arXiv{math.GT/0003187}.

\bibitem[GST]{GompfScharlemannThompson:Counterexample} R.~E.~Gompf,
  M.~Scharlemann, and A.~Thompson,
  {\em Fibered Knots and Potential Counterexamples to the Property 2R and
    Slice-Ribbon Conjectures,}
  Geom.\ and Top.\ {\bf 14} (2010) 2305--2347, \arXiv{1103.1601}.

\bibitem[MM]{MM} P.~M.~Melvin and H.~R.~Morton,
  {\em The coloured Jones function,}
  Commun.\ Math.\ Phys.\ {\bf 169} (1995) 501--520.

\bibitem[Ov]{Overbay:Thesis} A.~Overbay,
  {\em Perturbative Expansion of the Colored Jones Polynomial,}
  University of North Carolina PhD thesis, \web{Ov}.

\bibitem[Qu]{Quesne:Jackson} C.~Quesne,
  {\em Jackson's $q$-Exponential as the Exponential of a Series,}
  \arXiv{math-ph/0305003}.

\bibitem[Ro1]{Ro} L.~Rozansky,
  {\em A contribution of the trivial flat connection to the Jones
polynomial and Witten's invariant of 3d manifolds, I,}
  Comm.\ Math.\ Phys.\ {\bf 175-2} (1996) 275--296, \arXiv{hep-th/9401061}.

\bibitem[Ro2]{Rozansky:Burau} L.~Rozansky,
  {\em The Universal $R$-Matrix, Burau Representation and the Melvin-Morton
    Expansion of the Colored Jones Polynomial,}
  Adv.\ Math.\ {\bf 134-1} (1998) 1--31, \arXiv{q-alg/9604005}.

\bibitem[Ro3]{Rozansky:U1RCC} L.~Rozansky,
  {\em A Universal $U(1)$-RCC Invariant of Links and Rationality Conjecture,}
  \arXiv{math/0201139}.

\bibitem[Vo]{Vo:Thesis} H.~Vo,
  {\em Alexander Invariants of Tangles via Expansions,}
  University of Toronto Ph.D.\ thesis, in preparation.

\bibitem[Za]{Zagier:Dilogarithm} D.~Zagier,
  {\em The Dilogarithm Function,}
  in Cartier, Moussa, Julia, and Vanhove (eds) {\em Frontiers in Number
  Theory, Physics, and Geometry II.} Springer, Berlin, Heidelberg,
  and \web{Za}.

\end{thebibliography}}

\end{multicols}\vspace{-6mm}\begin{multicols}{2}

{\red\bf The Complete Implementation.}\hfill\web{SL2Portfolio}

An even fuller implementation is at \web{FullImp}.

\def\cellscale{0.645}
\newcount\snip
\snip=0\loop
  \advance \snip 1
  \par\needspace{20mm}\includegraphics[scale=\cellscale]{Snips/SL2Portfolio-\the\snip.pdf}
\ifnum \snip<58 \repeat

\end{multicols}

\def\N{\ding{56}}
\def\gY{\textcolor{ForestGreen}{\ding{52}}}
\def\oY{\textcolor{Orange}{\ding{52}}}
\def\headcell{
  diagram & \parbox{3in}{{\blue $n^t_k$}\quad Alexander's $\omega^+$
    \hfill genus / \textcolor{ForestGreen}{ribbon} \newline
  {\red Today's / Rozansky's $\rho_1^+$}
    \hfill unknotting number / \textcolor{Orange}{amphicheiral}}
}
\def\rolcell#1#2#3#4#5#6#7#8{
  \raisebox{-3pt}{\includegraphics[height=23pt]{../UNC-1610/KnotFigs/#1.pdf}}
& \parbox[b]{3.12in}{
    {\blue $#2$}\quad $#3$\hfill $#5$ / #7 \\
    {\red $#4$} \hfill $#6$ / #8
}}

{\footnotesize \begin{longtable}{|cl|cl|cl|}
\hline \headcell & \headcell \\ \endhead
\hline
\input ../GWU-1612/table.tex
\end{longtable}}

\end{document}

\endinput

