Proof of `Fourier analysis on a finite Boolean cube` (3rd statement)
groundedproofs/Lax323828Proofs/BooleanFourier.lean · lax-323828
What this proof establishes
no assumptions
Assuming the claims on the left, the claim on the right holds — checked by the archive's pipeline. Proof code is not displayed here.
Description
Expand the coefficients and interchange the two finite sums. The character kernel vanishes away from x and equals the size of the cube at x.