# Re: Logical Operators - another question

```On 08/09/2013 03:52 AM, Jens-D. Doll wrote:
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`Thanks Josh,`
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now I found it. The problem was, that I could not identify the symbol sets. After enabling one set it appears somewhere at the bottom, where several others already are shown....
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Just another question: How do I activate the \sqint symbol? The processor says: undefined symbol.
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In general, get yourself a copy of the comprehensive list of LaTeX symbols:
http://www.ctan.org/tex-archive/info/symbols/comprehensive/
Look up sqint, and see what packate it requires. Include said package.

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In this case, though, you can just go to Document> Settings> Math Options, and check "Include esint package automatically". That's the right package, and then LyX will take care of it.
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Richard

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