# dash over a letter [duplicate]

How do I write a letter like : A ,with a bar over it ( stands for the closure of A in topology) . I looked it up but \={A} didn't work , see : $$\={A}$$ .Help

## marked as duplicate by YuiTo Cheng, John Omielan, Asaf Karagila♦May 25 at 5:33

• For single letter, you can use \bar ( eg, \bar{A} $\to \bar{A}$). For putting a line over multiple letters, use \overline instead (e.g. \overline{ABC} $\to \overline{ABC}$). – achille hui May 25 at 1:37
• See the apt discussion of such accents and diacritical marks in Section 14 of the Question body for MathJax basic tutorial and quick reference, a good place for seeking similar tips and techniques. – hardmath May 25 at 3:18
• I'm curious as to where the \= idea came from... – Asaf Karagila May 25 at 5:32
• Text symbols ! ,short list (item 12 – StuartMN May 25 at 5:47

$$\overline{A}$$
• works also without the brackets: \overline A – Isabella May 25 at 1:29