The fact that the Fourier characters $\chi_{\gamma} : {\mathbb F}_2^n \to \{-1,1\}$ form a group isomorphic to ${\mathbb F}_2^n$ is not a coincidence; the analogous result holds for any finite abelian group and is a special case of the theory of Pontryagin duality in harmonic analysis. We will see further examples of this in Chapter [...]

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Ryan O'Donnell: Yes, thanks!Noam Lifshitz: In exercise 15 (Ex 18 in the book) is it true that $V_j=T_j$...Ryan O'Donnell: Thanks!Matt Franklin: Maybe two small typos in the proof of Corollary 11.67 (p. 36...Ryan O'Donnell: I see your point, although in some sense this distinction be...Ryan O'Donnell: Thank you!Ryan O'Donnell: Yep, thanks!