I would like to make a small horizontal spacing adjustment in the table of contents using amsbook. I find the horizontal space between "Chapter 1" and its title too large and similarly for sections and subsections and their numbers and titles. How to modify this space. In my MWE I made some other small adjustments of toc which I found on this site.
\documentclass[12pt]{amsbook}
\usepackage{etoolbox}
\setcounter{secnumdepth}{3}
\setcounter{tocdepth}{3}
% Uppercase 'CHAPTER' label in toc
\patchcmd{\tocchapter}{#1}{\MakeUppercase{#1}}{}{}
\makeatletter
% dots leading to the page number in toc
\renewcommand\@pnumwidth{1em}
\patchcmd{\@tocline}
{\hfil}
{\leaders\hbox{\,.\,}\hfil}
{}{}
% modify spacing in toc
\def\l@chapter{\@tocline{3}{5pt plus1pt}{0pc}{0pt}{}}
\def\l@section{\@tocline{2}{1pt plus1pt}{1.5pc}{0pt}{}}
\def\l@subsection{\@tocline{1}{1pt plus1pt}{4.5pc}{0pt}{}}
\makeatother
\renewcommand{\thesection}{\thechapter.\arabic{section}}
\begin{document}
\frontmatter
\title{My Book}
\author{Me}
% \date{}
\maketitle
\tableofcontents
\mainmatter
\chapter{Preliminaries}
\section{Section One}
\subsection{Subsection One}
\section{Section Two}
\subsection{Subsection One}
\subsection{Subsection Two}
\chapter{Results}
\section{Section One}
\subsection{Subsection One}
\subsection{Subsection Two}
\section{Section Two}
\subsection{Subsection One}
\subsection{Subsection Two}
\end{document}
'''
