Is there a LaTeX math package that provides "angle" accents?
For example, a "right angle accent" applied to "a" would look like this:
I produced this image using the COMBINING LEFT ANGLE ABOVE
Unicode character, which however does not seem to work in XeLaTeX, and there isn't a COMBINING RIGHT ANGLE ABOVE
character anyway.
If not, is there another recommendation to denote a lower / upper bound? I've seen the convention to use a "L"or "U" as sub- or superscripts, but don't like that.