\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}

\usepackage{geometry}
\usepackage{xcolor}

\AtBeginDocument{\everymath\expandafter{\the\everymath \displaystyle}
    \advance\lineskip\jot}

\usepackage{mathtools, amssymb}
\usepackage[nointegrals]{wasysym}
    \DeclareMathOperator\dom{\operatorname{dom}}
    \DeclareMathOperator\ran{\operatorname{ran}}
    \DeclarePairedDelimiter\abs{\lvert}{\rvert}
    \DeclarePairedDelimiter\norm{\lVert}{\rVert}
    \DeclarePairedDelimiter\floor{\lfloor}{\rfloor}
    \DeclarePairedDelimiter\ceil{\lceil}{\rceil}
    \def\bN{\mathbb N} \def\bZ{\mathbb Z} \def\bQ{\mathbb Q}
    \def\bR{\mathbb R} \def\bI{\mathbb I} \def\bO{\mathbb O}
    \def\mbb{\mathbb}
    \def\mfk{\mathfrak}

\usepackage{amsthm}
    \newtheorem{theorem}{Theorem}[section]
    \newtheorem{corollary}{Corollary}[theorem]
    \newtheorem{lemma}[theorem]{Lemma}
    \theoremstyle{definition}
    \newtheorem{definition}{Definition}[section]

\usepackage{chemfig}
\usepackage{lipsum}