# How to get Lyx to process aliases from the preamble in the graphical editing mode

I was trying to create my Lyx document in a structured way by defining a new latex command in the preample for the representation of complex conjugation, to keep all flexibility in case I would like to change it. In the preamble I added:

\let\cc\overline


How do I get Lyx to display the overline in the editor as I type my formulas?

In a LyX'ian way you can to the following instead of putting the definition in the LaTeX preamble.

### At the beginning of your document do:

1. Select menu "Insert" > "Math" > "Macro".
2. Type cc and select "Edit" > "Math" > "Macro Definition" > "Append Argument".
3. Go to the "TeX" field, mark/select the #1, and apply the style you like, e.g. type \overline + space

### Later in a math environment:

Type \cc + space and then type whatever variable or expression you what to have \cc applied on

Finally, a little picture about the two parts above:

One was is to enable instant preview for math (Tools > Preferences > Look & Feel > Display) and then use ERT inside of math (control + L). Or use ERT outside of math and use instant preview (select the ERT box and put Insert > Preview. If you do this though you have to enter math mode yourself in the ERT.

You might find useful information in Help > Math, in the section "User-defined Commands".