转载

1. \(\hat{A}\): \hat{A}

2. \(\widehat{A}\): \widehat{A}

3. \(\tilde{A}\): \tilde{A}

\widetilde{A}

\overline{A}

\underline{A}

\overbrace{A}

\underbrace{A}

\overset{a}{b}

\underset{a}{b}

\overleftarrow{A}

\overrightarrow{A}