我有这个文件：
\documentclass[12pt,a4paper]{extbook}
%---------------------------------------------
\usepackage{fontspec}
\setmainfont{Times New Roman}
\setsansfont{Arial}
\setmonofont{Courier New}
\newfontfamily\arabicfont[Script=Arabic,Scale=1.1]{Amiri}
%---------------------------------------------
\usepackage{fancyhdr}
\usepackage{amsmath}
\usepackage{amssymb}
%---------------------------------------------
\usepackage{polyglossia}
\makeatletter
\AtBeginDocument{\bidi@isloaded{arabxetex}}
\makeatother
\setdefaultlanguage{arabic}
\setotherlanguage{english}
%---------------------------------------------
\usepackage[novoc]{arabxetex}
%---------------------------------------------
\pagestyle{fancy}
\renewcommand{\headrulewidth}{1.5pt}
\renewcommand{\footrulewidth}{1.5pt}
\renewcommand{\baselinestretch}{1.5}
% bdAyt Alw_tyqT
\rhead{\textarab{Alf.sl Al'awl}}
\lhead{\textarab{`nwAn Alf.sl}}
%---------------------------------------------
\newtheorem{theorem}{n.zryT}
\renewcommand{\thetheorem}{\textLR{\arabic{theorem}}}
%---------------------------------------------
\begin{document}
\chapter{\textarab{alqsmT}}
\begin{arab}
\begin{theorem}
kl `dad yqbl alqsmT `l 1.
\end{theorem}
\begin{theorem}
kl `dad yqbl alqsmT `l nfsh.
\end{theorem}
\end{arab}
\end{document}
我想要数字 1、2、...
而不是“bab”，我想要“Alf.sl”
请问该怎么办？
非常感谢