\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{graphicx}
\usepackage[top=1.0 in, left=1.0 in, bottom=1.0 in, right=1.0 in]{geometry}
%These are common logical symbols you may need 
\def\not{\neg}
\def\implies{\Rightarrow}
\def\and{\wedge}
%Note, we avoid \or because it gives trouble elsewhere
%We use \vel for the inclusive or and \aut for the exclusive or
\def\vel{\vee}
\def\aut{\times}
\def\iff{\Leftrightarrow}
\def\tilde{\sim}
\def\bar#1{\overline{#1}}
\def\margin#1{ \marginpar{{\tiny #1}}}
\setlength{\parindent}{0in}
\setlength{\parskip}{+.2in}
\def\fat{\mathbb}
\def\fatfunc#1{$\fat{$1}\ $}
\def\cngr{\equiv}
\setlength{\parindent}{0pt}
\pagestyle{empty}

\begin{document}

{\large \bf  Twas brillig and the slithey toves.} 

\[ A \implies B,   A \and B  ,  A \vel B  ,   A \tilde B, 
 A \cngr B 
  \neg{ A \and B \vel C \implies \bar{D} \in \fat{N}},
 X \iff Y
\]

\end{document}
