Overline-Style for Not-Expression for text

Hello Community,

i want to make my own simple Expression Language that looks more mathematical than the default one.

My problem is the overline for the Not-Statement (https://en.wikipedia.org/wiki/Overline). I can only find the StyleClassItem for underlined.

Is there a way to have the same functionality (children inherit true or false with as_is from parent)  like underlined but with the line above the text?

Best Regards

Kai Meinhard