In book Modern theory of critical phenomena author Shang - Keng Ma in page 17.(adsbygoogle = window.adsbygoogle || []).push({});

[tex]\sigma_{\vec{k}}=V^{-\frac{1}{2}}\int d^3\vec{x}e^{-i\vec{k}\cdot\vec{x}}\sigma(\vec{x})[/tex]

[tex]\sigma(\vec{x})=V^{-\frac{1}{2}}\sum_{\vec{k}}e^{i\vec{k}\cdot \vec{x}}\sigma_{\vec{k}}[/tex]

Is this correct? How can inversion of continual FT be discrete FT? Thanks for your answer.

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# Mistake in book?

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