overline not working with multiple characters (even in Latex Mode)

[Rom1-GoPlay]

Hi ! I Love Nabla, this app is really useful !! But I am facing a problem: I would like to display something like:

But I am not able. Without latex mode the bar cover only the last character (I get: z + z'̅ ).

With latex mode I try to type: \overline{z + z'} (between initial string and end string) and I get: \overline{z + z'} (the same without initial and end strings)

Notice that with a single characters I get the expected result: z̅ with \overline{z}

[ray-pH]

I don't think you can do that. It's the limitation of Unicode. What's available in Unicode are "combining overline" (U+0305 ◌̅) and "combining double macron" (U+035E ◌͞).

Even with just normal words, it looks weird because the height of each letter is different https://www.reddit.com/r/Unicode/comments/8msm2j/can_i_overline_an_entire_word/ using combining overline U+0305: s̅i̅g̅n̅a̅l̅ … T̅e̅s̅t̅ … f̅u̅l̅l̅-̅t̅i̅m̅e̅ ̅w̅o̅r̅k̅ using combining double macron U+035E: s͞i͞g͞n͞a͞l … T͞e͞s͞t … f͞u͞l͞l͞-͞t͞i͞m͞e͞ ͞w͞o͞r͞k͞

[Rom1-GoPlay]

Thanks ! But why is this working on logseq ? When I type: \overline{z + z'} In logseq (a note app) on my desktop, I get the expected result. I guess logseq doesn't use unicode to render the formula.

[ray-pH]

yeah, logseq doesn't use Unicode, they use some renderer to render their equation (I believe they use KaTeX). On platforms that support rendering math expressions (like logseq, or even GitHub*), you can easily write $\overline{z+z'}$ ($\overline{z+z'}$). But you can't copy-paste them outside those platforms, they act pretty much like an image. $$\overline{z+z'}$$ Outside of those platforms, Unicode is the best you can do.

*only in GitHub desktop, apparently the mobile app doesn't support math rendering