\documentclass[12pt,a4paper]{book} 
\usepackage{epsfig}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage{tabularew}
\usepackage{thmtools}
\usepackage{pst-plot}
\usepackage[pdftex]{graphicx}
\usepackage{graphicx}
\textwidth 6.80in
\topmargin -0.50in
\oddsidemargin 0in
\evensidemargin 0in
\textheight 9.00in
\renewcommand{\baselinestretch}{1.5}
\usepackage{xepersian}
\newcommand{\threenumi}{\alph{a}}
\newcommand{\threenumii}{\alph{enumii}}
\renewcommand{\thefootnote}{\fnsymbol{footnote}}
\newcommand{\threenumiii}{\alpha{enumiii}}
\newcommand{\threenumiv}{\alph{enumiv}}
\newcommand{\threenumv}{\alph{enumv}}
\theoremstyle{definition}
\newtheorem{definition}{تعریف}[section]
\theoremstyle{theorem}
\newtheorem{theo}[definition]{قضیه}
\newtheorem{lemma}[definition]{لم}
\newtheorem{prop}[definition]{گزاره}
\newtheorem{coro}[definition]{نتیجه}
\newtheorem{remark}[definition]{ملاحظه}
\newtheorem{nok}[definition]{نکته}
\newtheorem{nok-def}[definition]{نکته و تعریف}
\newtheorem{def-nok}[definition]{تعریف و نکته}
\theoremstyle{definition}
\newtheorem{ex}[definition]{مثال}
\newtheorem{conj}[definition]{فرضیه}
\newcommand{\bd}{\begin{definition}}
\newcommand{\ed}{\end{definition}}
\settextfont[Scale=1.3]{B Nazanin}
\setlatintextfont[Scale=1.3]{Times New Roman}
\setdigitfont{XB Zar}
\defpersianfont\iranic[Scale=1.4]{XB Zar}
\defpersianfont\NazaninBold[Scale=1.2]{B Nazanin Bold}
\defpersianfont\AbstractBold[Scale=1.2]{B Nazanin Bold}
\begin{document}
\end{document}