dissertation_work/Scratch/Neural network diffeq.tex

179 lines
8.1 KiB
TeX
Raw Normal View History

2024-02-19 17:04:37 +00:00
\documentclass[11pt]{report}
\usepackage{setspace}
\doublespacing
\usepackage[toc,page]{appendix}
\usepackage[]{amsmath}
\usepackage[]{amsthm}
\usepackage{mathtools}
\numberwithin{equation}{section}
\usepackage[]{amssymb}
\usepackage[margin=1in]{geometry}
\usepackage[]{soul}
\usepackage[]{bbm}
\usepackage[]{cancel}
\usepackage[]{xcolor}
\usepackage[]{enumitem}
\usepackage{mathrsfs}
\usepackage{hyperref}
\usepackage[capitalise]{cleveref}
\usepackage{natbib}
\usepackage{neuralnetwork}
\usepackage{witharrows}
\usepackage{listings}
\usepackage{graphicx}
\DeclareMathAlphabet{\mymathbb}{U}{BOONDOX-ds}{m}{n}
% \usepackage[]{enumerate}
\setlength\parindent{0pt}
\DeclareMathOperator{\Trace}{Trace}
\DeclareMathOperator{\Hess}{Hess}
\DeclareMathOperator{\supp}{supp}
\DeclareMathOperator{\domain}{Domain}
\DeclareMathOperator{\lip}{Lip}
\usepackage{tikz-cd}
\DeclareMathOperator{\rect}{Rect}
\DeclareMathOperator{\param}{Param}
\DeclareMathOperator{\inn}{In}
\DeclareMathOperator{\out}{Out}
\DeclareMathOperator{\neu}{NN}
\DeclareMathOperator{\hid}{Hid}
\DeclareMathOperator{\lay}{Lay}
\DeclareMathOperator{\dep}{Dep}
\DeclareMathOperator{\we}{Weight}
\DeclareMathOperator{\bi}{Bias}
\DeclareMathOperator{\aff}{Aff}
\DeclareMathOperator{\act}{Act}
\DeclareMathOperator{\real}{Rlz}
\DeclareMathOperator{\id}{Id}
\DeclareMathOperator{\mult}{Mult}
\DeclareMathOperator{\wid}{Wid}
\DeclareMathOperator{\sm}{Sum}
\DeclareMathOperator{\trn}{Trn}
\DeclareMathOperator{\cpy}{Copy}
\DeclareMathOperator{\ex}{Ex}
\DeclareMathOperator{\lin}{Lin}
\DeclareMathOperator{\relu}{ReLU}
\DeclareMathOperator{\zero}{Zr}
\DeclareMathOperator{\obj}{obj}
\DeclareMathOperator{\dom}{dom}
\DeclareMathOperator{\cod}{cod}
\newcommand{\bbP}{\mathbb{P}}
\newcommand{\E}{\mathbb{E}}
\newcommand{\R}{\mathbb{R}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\N}{\mathbb{N}}
\newcommand{\p}{\mathfrak{p}}
\newcommand{\mft}{\mathfrak{t}}
\newcommand{\f}{\mathfrak{f}}
\newcommand{\C}{\mathfrak{C}}
\newcommand{\n}{\mathscr{N}}
\newcommand{\lp}{\left(}
\newcommand{\rp}{\right)}
\newcommand{\rb}{\right]}
\newcommand{\lb}{\left[}
\newcommand{\lv}{\left|}
\newcommand{\rv}{\right|}
\newcommand{\la}{\langle}
\newcommand{\ra}{\rangle}
\newcommand{\ve}{\varepsilon}
\newcommand{\les}{\leqslant}
\newcommand{\ges}{\geqslant}
% Input layer neurons'number
\newcommand{\inputnum}{3}
% Hidden layer neurons'number
\newcommand{\hiddennum}{5}
% Output layer neurons'number
\newcommand{\outputnum}{2}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{corollary}{Corollary}[theorem]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{claim}[theorem]{Claim}
\title{Reformulation without f}
\author{Shakil Rafi}
\begin{document}
\maketitle
\begin{lemma}
Let $\Theta = \bigcup_{n\in\N}$, $d,m,\mathfrak{d} \in \N$, $T \in (0,\infty)$, $\act \in C \lp \R,\R\rp$, $\mathfrak{I}, \mathbf{F}, \mathbf{G} \in \neu$ satisfy $\lay\lp \mathfrak{I} \rp = \lp 1,\mathfrak{d},1\rp$, $\real_{\act} \lp \mathfrak{I} \rp = \mathbb{I}_1$, $\real_{\act} \lp \mathbf{F} \rp \in C\lp \R, \R \rp$, and $\real_{\act} \lp \mathbf{G} \rp \in C \lp \R^d, \R \rp$, for every $\theta \in \Theta$ let $\mathcal{U}^\theta: \lb 0,T \rb \rightarrow \lb 0,T \rb$ and $\mathcal{W}^\theta : \lb 0,T \rb \rightarrow \R^d$, be functions, for every $\theta \in \Theta$, $n\in \N_0$ let $U^\theta_n: [0,T] \times \R^d \rightarrow \R$ satisfy for all $t\in [0,T]$, $x \in \R^d$, that:
\begin{align*}
&U^\theta_n(t,x) = \frac{\mymathbb{1}_\N (n)}{M^n} \lb \sum^{m^n}_{k=1} \lp \real_{\act} \lp \mathbf{G}\rp \rp \lp x+\mathcal{W}^{\lp \theta,0,-k \rp}_{T-t} \rp \rb \\
&+\sum^{n-1}_{i=1} \frac{T-t}{M^{n-i}} \lb \sum^{M^{n-i}}_{k=1} \lp \lp \real_{\act} \lp \mathbf{F}\rp \circ U_i^{(\theta,i,k)} \rp -\mymathbb{1}_\N \lp i \rp \lp \real_{\act} \lp \mathbf{F}\rp \circ U^{\lp \theta,-i,k \rp} \rp \rp \lp \mathcal{U}_t^{\lp \theta,i,k \rp},x+\mathcal{W}^{\lp\theta,i,k\rp}_{\mathcal{U}_t^{\lp \theta,i,k\rp}-t} \rp \rb
\end{align*}
and let $\mathbf{U}^\theta_{n,t} \in \neu$, $t \in [0,T]$, $n\in \Z$, $\theta \in \Theta$, satisfy for all $\theta \in \Theta$, $n\in \N$, $t\in [0,T]$ that $\mathbf{U}^\theta_{0,t} = \lp \lp 0 \:0\:\cdots \:0 \rp,0 \rp \in \R^{1 \times d} \times \R$ and:
\begin{align*}
\mathbf{U}^\theta_{n,t} &= \lb \oplus^{M^n}_{k=1} \lp \frac{1}{M^n} \circledast \lp \mathbf{G}\bullet \aff_{\mathbb{I}_d, \mathcal{W}^{\lp \theta,0,-k \rp }_{T-t}} \rp \rp \rb \\ &\boxplus_{\mathfrak{I}} \lb \boxplus_{i=0,\mathfrak{I}} \lb \lp \frac{T-t}{M^{n-i}}\rp \circledast \lp \boxplus^{M^{n-i}}_{k=1,\mathfrak{I}}\lp \lp \mathbf{F}\bullet \mathbf{U}^{\lp \theta,i,k \rp}_{i,\mathcal{U}_t^{\lp \theta,i,k \rp}}\rp \bullet \aff_{\mathbb{I}_d,\mathcal{W}^{\lp \theta,i,k \rp}_{\mathcal{U}^{\lp \theta,i,k \rp}-t}} \rp \rp \rb \rb \\
&\boxplus_{\mathfrak{I}}\lb \boxplus^{n-1}_{i=0,\mathfrak{I}}\lb \lp \frac{(t-T)\mymathbb{1}_\N \lp i \rp }{M^{n-i}} \rp \circledast \lp \boxplus^{M^{n-i}}_{k=1,\mathfrak{I}}\lp \lp \mathbf{F}\bullet \mathbf{U}^{\lp \theta,-i,k \rp }_{\max\{i-1,0\},\mathcal{U}_t^{\lp \theta,i,k \rp}} \rp \bullet \aff_{\mathbb{I}_d,\mathcal{W}^{\lp \theta,i,k \rp }_{\mathcal{U}_t^{\lp \theta,i,k \rp}-t}}\rp \rp \rb \rb
\end{align*}
\end{lemma}
\begin{theorem}\label{thm1}
Let $p,q,r,L,C,\alpha_0,\alpha_1,\beta_0,\beta_1, T \in [0,\infty)$, $\mathfrak{q} \in [2,\infty)$, $\act \in C(\R,\R)$, $\mathfrak{I} \in \neu$. $\lp \mathbf{F}_{d,\ve} \rp _{\lp d,\ve \rp \in \N_0 \times (0,1]} \subsetneq \neu$. For every $d \in \N_0$ let $f_d \in C \lp \R^{\max\{d,1\}},\R \rp$, for every $d \in \N$ let $\nu_d: \mathcal{B} \lp \R^d \rp \rightarrow [0,1]$ be a probability measure, and assume for all $d \in \N_0$, $v,w \in \R$, $x \in \R^{\max\{d,1\}}$, $\ve \in (0,1]$ that $\lp \int_{\R^d}\left\|y\right\|^{pq\mathfrak{q}} \nu_d \lp dy\rp \rp ^{\frac{1}{pq\mathfrak{q}}}\les Cd^r$, $\hid\lp \mathfrak{I} \rp=1$, $\real_{\act} \lp \mathfrak{I} \rp = \id_\R $, $\real_{\act} \lp \mathbf{F}_{d,\ve} \rp \in C \lp \R^{\max\{d,1\}},\R \rp $, $\max \{ \left|f_0(v)-f_0(w)\right|, \left|\lp \real_{\act} \lp \mathbf{F}_{0,\ve} \rp \rp \lp x \rp - \lp \real_{\act} \lp \mathbf{F}_{0,\ve} \rp \rp \lp x \rp \right|\} \les L \left|v-w\right|$, $\ve^{\alpha_{\min\{d,1\}}}\dep \lp \mathbf{F}\rp_{d,\ve}+\ve^{\beta_{\min\{d,1\}}}\left\| \lay \lp \mathbf{F}_{d,\ve} \rp \right\|_{\max} \les C \lp \max \{x,1\}^p \rp$, and:
\begin{align}
\ve \left| \lp \real_{\act} \lp \mathbf{F}_{d,\ve}\rp \rp \lp x \rp \right| + \left|f_d\lp x\rp - \lp \real_{\act}\lp \mathbf{F}_{d,\ve} \rp \rp \lp x \rp \right| \les \ve C \lp \max \{x,1\}\rp ^p \lp 1+ \left\|x \right\| \rp ^{pq}
\end{align}
It is then the case that for every $d \in \N$, there exists a $u_d \in C \lp \lb 0,T \rb \in \R^d,\R \rp$ with the following properties:
\begin{enumerate}[label = (\roman*)]
\item $u_d$ is polynomially growing.
\item $u_d$ is a viscosity solution.
\item $u_d$ is a solution to:
\begin{align}
\lp \frac{\partial}{\partial t} u_d \rp \lp t,x \rp +\frac{1}{2}\Trace\lp \sigma_d \lp x \rp \lb \sigma_d \lp x \rp \rb ^*\lp \Hess_x u_d \rp \lp t,x\rp \rp + \la u_d \lp x \rp, \lp \nabla_xu_d \rp \lp t,x \rp \ra + \alpha_d(x)u_d(t,x)= 0 \nonumber
\end{align}
with $u_d \lp T,x \rp =g_d \lp x \rp$ for $\lp t,x \rp \in \lp 0,T \rp \times \R^d$, and
\item there exist $\lp \mathbf{U}_{d,t,\ve} \rp _{ \lp d,t,\ve \rp \in \N \times \lb 0,T \rb \times \lp 0,1\rb}$ and $\eta \in \lp \eta_\delta \rp _{\delta \in \lp 0,\infty \rp}: \R \rightarrow \R$ such that for all $d \in \N$, $t \in \lb 0,T \rb$, $\ve \in (0,1]$, $\delta \in \lp 0,\infty \rp $ it holds that $\real_{\act} \lp \mathbf{U}_{d, t,\ve} \rp \in C \lp \R^d, \R \rp$, $\param \lp \mathbf{U}_{d,t,\ve} \rp \les \eta_\delta d^{p\lp 7+4q+ \lp 2+q \rp \delta \rp } \ve ^{-\lp 4+2\delta + \max\{\alpha_0,\alpha_1\}+2\max\{\beta_0,\beta_1\} \rp}$ and:
\begin{align}
\lp \int_{\R^d} \left|u_d\lp t,x \rp -\lp \real_{\act} \lp \mathbf{U}_{d,t,\ve} \rp \rp \lp x \rp \right|^\mathfrak{q} \nu_d \lp dx\rp \rp ^{\frac{1}{\mathfrak{q}}} \les \ve
\end{align}
\end{enumerate}
\end{theorem}
\begin{proof}
The proof of Theorem \ref{thm1} is thus complete
\end{proof}
\end{document}