[Tex/LaTex] Undefined control sequence \coloneqq


I'm trying to export a PDF of a LyX document (it has never caused a problem before). Below I have posted pictures of the error message along with the equation LyX highlighted for me. I don't know what \hbox is, and I didn't use that in my code. Can someone please help me edit the equation so that I can export a PDF?

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Best Answer

The command \coloneqq is unknown, you need to load a package for this, such as mathtools, txfonts or pxfonts.

Add to your document preamble:


LyX 2.1 will have direct mathtools support.