% STYLE-FILE FOR COMBINATORIAL THEORY

% PACKAGES
\usepackage[a4paper,twoside]{geometry}
\usepackage{amssymb,amsmath,amsthm,amsfonts}
\usepackage{graphicx}
\usepackage{tgtermes}
\usepackage[noblocks]{authblk}
\usepackage{xparse} % see comment (*) below
\usepackage{color}
\usepackage[usenames,dvipsnames,svgnames,table]{xcolor}
\usepackage[colorlinks=true,citecolor=blue,linkcolor=blue,urlcolor=black]{hyperref}
\usepackage[noabbrev,capitalise]{cleveref}

% GEOMETRY
\setlength{\textwidth}{6.3in}
\setlength{\textheight}{8.7in}
\setlength{\topmargin}{0pt}
\setlength{\headsep}{16pt}
\setlength{\headheight}{4pt}
\setlength{\oddsidemargin}{0pt}
\setlength{\evensidemargin}{0pt}

% FONTS
% default fonts
\renewcommand{\familydefault}{qtm}
\renewcommand\Authfont{\fontsize{12}{14.4}\selectfont}
\newcommand\smAuthfont{\fontsize{9}{14.4}\selectfont}
% fonts and spacing in title, section, and paragraphs headings.
\renewcommand\title[1]{\gdef\@title{\reset@font\scshape #1}}
\renewcommand\section{\@startsection{section}{1}{\z@}{-3.5ex \@plus -1ex \@minus -.2ex}{2.3ex \@plus.2ex}{\normalfont\large\bfseries}}
\renewcommand\subsection{\@startsection{subsection}{2}{\z@}{-3ex\@plus -1ex \@minus -.2ex}{1.5ex \@plus .2ex}{\normalfont\normalsize\bfseries}}
\renewcommand\subsubsection{\@startsection{subsubsection}{3}{\z@}{-2.5ex\@plus -1ex \@minus -.2ex}{1.5ex \@plus .2ex}{\normalfont\normalsize\bfseries}}
\renewcommand\paragraph{\@startsection{paragraph}{4}{\z@}{2ex \@plus.5ex \@minus.2ex}{-1em}{\normalfont\normalsize\bfseries}}
\renewcommand\subparagraph{\@startsection{subparagraph}{5}{\parindent}{2ex \@plus.5ex \@minus .2ex}{-1em}{\normalfont\normalsize\bfseries}}
% fonts in author addresses and emails
\renewcommand\Affilfont{\fontsize{9}{10.8}\itshape}
\newcommand\emailfont{\sffamily}
\newcommand*{\email}[1]{\href{mailto:#1}{\emailfont#1} } 
% fonts in header appearing on all pages.
\newfont{\headsc}{cmcsc10 at 8truept}
\newfont{\headbf}{cmbx10 at 8truept}
\newfont{\headrm}{cmr10 at 10truept}
\newfont{\headtt}{cmtt10 at 10truept}

% TITLE
% dateline
\newcommand{\dateline}[3]{\footnotesize \def\the@dateline{%
	Submitted: \ignorespaces#1;
	Accepted: \ignorespaces#2;
	Published: \ignorespaces#3%
}}
% copyright
\def\copy@right{\copyright \thinspace The author{\ifnum\value{authors}>1 s\fi}. Released under the CC BY license (International 4.0).}
% title, including dateline and copyriht
\let\old@maketitle\maketitle
\renewcommand{\maketitle}{\date{\small\the@dateline\\[0.5ex]\copy@right}\old@maketitle}

% ABSTRACT
% keywords
\newcommand{\keywords}[1]{\def\the@keywords{\ignorespaces#1}}
% MSC classes
\newcommand{\MSC}[1]{\def\the@MSC{\ignorespaces#1}}
% abstracts presentation, including keywords and MSC classes
\def\abstractheadfont{\bfseries}
\def\@setabstracthead{{\abstractheadfont\abstractname}}
\renewenvironment{abstract}{%
	\small\quotation
	\noindent{\abstractheadfont{\abstractname}}.\normalfont
}{
	\par\smallskip\noindent\textbf{Keywords.} \the@keywords
	\par\smallskip\noindent\textbf{Mathematics Subject Classifications.} \the@MSC
	\endquotation
}
% no table of contents
\renewcommand{\tableofcontents}{}
\renewcommand{\listoffigures}{}
\renewcommand{\listoftables}{}

% PREPARE INFORMATIONS FOR HEADERS
% get specifications of the paper
\newcommand{\specs}[4]{\def\papno{#1}\def\volno{#2}\def\volyear{#3}\def\papid{#4}}
\ifx\volno\undefined\def\volno{27}\fi
\ifx\volyear\undefined\def\volyear{2020}\fi
\ifx\papno\undefined\def\papno{P00}\fi
\ifx\papid\undefined\def\papid{abcd}\fi
% format authors in header
\let\authblkauthor\author
\ExplSyntaxOn
\seq_new:N \g_ct_authors_seq
\RenewDocumentCommand{\author}{om}{
	\seq_gput_right:Nn \g_ct_authors_seq { #2 }
	\IfNoValueTF { #1 } { \authblkauthor{#2} } { \authblkauthor[#1]{#2} }
}
% The following command returns the m-th author
\NewDocumentCommand{\ABgetauthor}{m}{\seq_item:Nn \g_ct_authors_seq {#1}}
\ExplSyntaxOff
\newcommand*{\authorshead}{%
	\begingroup
	\renewcommand\footnotemark[1][]{}% ignore \footnotemark
	\let\footnote\@gobble% ignore \footnote
	\let\thanks\@gobble% ignore \thanks
	\let\textsuperscript\@gobble% ignore protected \textsuperscript
	\expandafter\let\csname textsuperscript \endcsname\@gobble
	\let\Authfont\relax% do not use a special font
	\def\Authand{, }% separate list of authors by ,
    \ifnum\value{authors}<3 % one ore two authors
		\AB@authlist% show them all
	\else% 3 or more authors
	\ABgetauthor{1}\,et~al.
	\fi
	\endgroup
}
% ----------------------------
% Comment (*)
% The following solution would ideally have
% \NewCommandCopy{\authblkauthor}{\author}
% 		instead of
% \let\authblkauthor\author
% but this requires everyone to have the newest LaTeX.
% Likewise, we load xparse so that we can use \ReNewCommand. This
% is also in the newest LaTeX kernel.
% ----------------------------

% HEADERS
\renewcommand{\ps@plain}{%
	\ps@headings
	% headers
	\renewcommand{\@evenhead}{{\headsc \thepage} \hfil \smAuthfont \authorshead}
	\renewcommand{\@oddhead}{
		\headsc combinatorial theory {\headbf\volno} (\volyear), \#\papno \hfil \ifnum\value{page}>1{\thepage}
		\else\href{https://www.combinatorial-theory.org}{\headtt combinatorial-theory.org}\fi
	}
	% footers
	\renewcommand{\@evenfoot}{}
	\renewcommand{\@oddfoot}{}
}
\pagestyle{plain}

% THEOREMS
% theorems
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{corollary}[theorem]{Corollary}
\newtheorem{proposition}[theorem]{Proposition}
\newtheorem{fact}[theorem]{Fact}
\newtheorem{observation}[theorem]{Observation}
\newtheorem{claim}[theorem]{Claim}
% definitions
\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{example}[theorem]{Example}
\newtheorem{conjecture}[theorem]{Conjecture}
\newtheorem{open}[theorem]{Open Problem}
\newtheorem{problem}[theorem]{Problem}
\newtheorem{question}[theorem]{Question}
% remarks
\theoremstyle{remark}
\newtheorem{remark}[theorem]{Remark}
\newtheorem{note}[theorem]{Note}
% change numbering of some things to within section
\numberwithin{equation}{section}
\numberwithin{figure}{section}
\numberwithin{table}{section}
\theoremstyle{theorem}

% BIBLIOGRAPHY
% Squashing the bibliography
\newlength{\BiblioSpacing}
\setlength{\BiblioSpacing}{0.4ex plus 0.1ex minus 0.1ex}
\let\oldthebibliography\thebibliography
\let\endoldthebibliography\endthebibliography
\renewenvironment{thebibliography}[1]{
	\begin{oldthebibliography}{#1}
	\setlength{\parskip}{\BiblioSpacing}
	\setlength{\itemsep}{\BiblioSpacing}
}{
    \end{oldthebibliography}
}
% arXiv reference
\newcommand{\arxiv}[1]{\href{https://arxiv.org/abs/#1}{\texttt{arXiv:#1}}}
% Typeset a doi (some magic to make underscores work)
\def\doi{\begingroup\catcode`\_=12\relax\doi@arg}
\def\doi@arg#1{\href{https://doi.org/#1}{\texttt{https://doi.org/#1}}\endgroup}

% OTHERS
% section formatting
\def\@seccntformat#1{\@ifundefined{#1@cntformat}%
   {\csname the#1\endcsname\space}% default
   {\csname #1@cntformat\endcsname}}% enable individual control
\newcommand\section@cntformat{\thesection.\space} % section-level
\newcommand\subsection@cntformat{\thesubsection.\space} % subsection-level

% fix math symbols
\renewcommand{\geq}{\geqslant}
\renewcommand{\leq}{\leqslant}
\renewcommand{\ge}{\geqslant}
\renewcommand{\le}{\leqslant}
\renewcommand{\emptyset}{\varnothing}
