latex中符号记录

a \stackrel{b} {\longrightarrow} c \\
a \stackrel{b} {\longleftarrow} c \\
\vec{A} \\
\mathop{n}\limits ^{\rightarrow} \\
\mathop{n}\limits ^{\leftarrow} \\
\widehat{A}\\
\hat{A} \\
\widecheck{A} \\
\check{A} \\
\widetilde{A} \\
\tilde{A} \\
\overline{A} \\
\underline{A} \\
\dot{A} \\
\ddot{A} \\
\dddot{A} \\
\ddddot{A} \\
\mathring{A} \\
\breve{A} \\
\grave{A} \\
\acute{A} \\
\bar{A}