Proof of `Orthogonality and finite Walsh correlation bounds` (5th statement)
groundedproofs/Lax342547Proofs/Walsh.lean · lax-342547
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 square and interchange the three finite sums. Orthogonality kills every off-diagonal pair and contributes exactly 2^d on the diagonal.