As we all know, the long arrows can be used with amsmath or extarrows: \xleftarrow, \xLongleftarrow etc.

However, these macros simply employ minus or equals and may not be so pretty. With unicode-math, for example, XITS Math has defined the long arrows with OpenType feature horizontal construction. How to use it in LaTeX?


1 Answer 1


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Luatex has a \Uhextensible primitive to access horizontal stretch feature in the font.



\setmathfont{TeX Gyre Termes Math}



$\Uhextensible width 5cm 0 "2192$

$\Uhextensible width 6cm 0 "2194$

$\Uhextensible width 7cm 0 "21D2$

  • 1
    I don't think the horizontal extension mechanism is available in xetex Commented Mar 29, 2018 at 16:30
  • It seems that \Uhextensible is only available in luatex.
    – stone-zeng
    Commented Mar 29, 2018 at 16:35
  • And how to add text under/below the arrow?
    – stone-zeng
    Commented Mar 29, 2018 at 16:35
  • 1
    @Stone-Zeng text above and below you would do as in (the definition o)f the x... arrows from amsmath so $\mathop{\Uhextensible width 5cm 0 "2192}\limits_{\mathrm{text}}$ it would need a proper top level command defining but partly as it only works in luatex this hasn't been used much I expect. It works though. Commented Mar 29, 2018 at 16:42

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