Display Function Cannot Combine Vector Arrows with Subscripts In Jupyter Notebooks

[NSC9]

I am using Sympy v1.9

display(Symbol('v\u20D7'))
v0,v0x=symbols('v_0 v_0x')
display(v0,v0x)
display(Symbol(f'{v0}\u20D7'))

As one can see, splicing a subscripted symbol into another symbol to add a vector on top simply puts the arrow above the subscripted zero.

[sylee957]

I'm not familiar about the tricks with \u20D7, however, it looks you are using the unicode combining characters. https://en.wikipedia.org/wiki/Combining_character

However, I don't think that the combining character is compatible with every LaTeX as you expected, beyond basic cases,
and I don't think that this is any issue with SymPy, because it happens before SymPy. v_0\u20D7 is interpreted as 3 glyphs, v, _, 0\u20D7.

Obviously, there are more advanced tricks with unicode that may work around this, and you may combine with unicode subscripts, such as Symbol('v\u20D7\u2080') for workaround, however, that may not be desirable because you may face much more confusing compatibility issues with LaTeX later.

I may suggest to wrap symbol names inside LaTeX control sequences like \overrightarrow, such as
Symbol('\overrightarrow{v_0}') and it should display correctly as $\overrightarrow{v_0}$

I also generally suggest to avoid tricks with unicode, and try to find LaTeX control sequences that does same work. I rarely use unicode combining characters, or unicode subscripts or superscripts, because they are not sufficient for many math formula.