Root-Hadamard transforms and complementary sequences
Pith reviewed 2026-05-24 17:58 UTC · model grok-4.3
The pith
The root-Hadamard transform generalizes Walsh-Hadamard, nega-Hadamard and related transforms on generalized Boolean functions.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
We define a new transform on (generalized) Boolean functions, which generalizes the Walsh-Hadamard, nega-Hadamard, 2^k-Hadamard, consta-Hadamard and all HN-transforms. We describe the behavior of what we call the root-Hadamard transform for a generalized Boolean function f in terms of the binary components of f. Further, we define a notion of complementarity (in the spirit of the Golay sequences) with respect to this transform and furthermore, we describe the complementarity of a generalized Boolean set with respect to the binary components of the elements of that set.
What carries the argument
The root-Hadamard transform, defined uniformly on generalized Boolean functions and reducing to known transforms on binary components while supporting complementarity.
Load-bearing premise
The root-Hadamard transform can be defined uniformly on generalized Boolean functions such that its action on binary components yields the stated complementarity properties without additional domain restrictions or counterexamples.
What would settle it
A counterexample would be a generalized Boolean function where the root-Hadamard transform does not match the expected behavior on its binary components or where complementarity fails to transfer as described.
read the original abstract
In this paper we define a new transform on (generalized) Boolean functions, which generalizes the Walsh-Hadamard, nega-Hadamard, $2^k$-Hadamard, consta-Hadamard and all $HN$-transforms. We describe the behavior of what we call the root- Hadamard transform for a generalized Boolean function $f$ in terms of the binary components of $f$. Further, we define a notion of complementarity (in the spirit of the Golay sequences) with respect to this transform and furthermore, we describe the complementarity of a generalized Boolean set with respect to the binary components of the elements of that set.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper defines a root-Hadamard transform on generalized Boolean functions f: Z_2^n → Z_q, asserting that this single definition generalizes the Walsh-Hadamard, nega-Hadamard, 2^k-Hadamard, consta-Hadamard, and all HN-transforms. It describes the transform's action via the binary components of f, introduces a complementarity notion for such functions (in the spirit of Golay sequences), and extends the complementarity description to sets of generalized Boolean functions via their binary components.
Significance. If the uniform definition recovers each listed classical transform exactly on binary components while preserving the stated complementarity relations for all q (including composite cases) and without unstated restrictions on support or codomain, the work would supply a useful unifying framework for Hadamard-type transforms and complementary sequences in coding theory. The explicit reduction to binary components is a constructive element that could support further constructions.
major comments (1)
- [Definition of the root-Hadamard transform and its action on binary components] The load-bearing claim that one uniform definition of the root-Hadamard transform generalizes all listed transforms on binary components is not accompanied by explicit verification that the reduction matches each classical case. When q is composite or the support of f is unbalanced, the weighting or matrix construction may fail to reproduce the consta-Hadamard or HN-transforms exactly, which would invalidate the complementarity claims for generalized sets.
minor comments (1)
- The abstract refers to 'all HN-transforms' without defining the acronym or citing the relevant prior works in the introduction or preliminaries.
Simulated Author's Rebuttal
We thank the referee for the careful review and the constructive major comment. We address it point by point below and will revise the manuscript to incorporate the requested clarifications.
read point-by-point responses
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Referee: [Definition of the root-Hadamard transform and its action on binary components] The load-bearing claim that one uniform definition of the root-Hadamard transform generalizes all listed transforms on binary components is not accompanied by explicit verification that the reduction matches each classical case. When q is composite or the support of f is unbalanced, the weighting or matrix construction may fail to reproduce the consta-Hadamard or HN-transforms exactly, which would invalidate the complementarity claims for generalized sets.
Authors: The root-Hadamard transform is defined uniformly via a weighting matrix constructed from q-th roots of unity so that its action on the binary components of f recovers each classical transform by design. Section 3 derives the explicit action on binary components and states the reductions. We agree, however, that the manuscript would be strengthened by explicit verification for each listed case. In the revision we will add a short appendix that tabulates the reduction for the Walsh-Hadamard, nega-Hadamard, 2^k-Hadamard, consta-Hadamard and HN-transforms, including the composite-q and unbalanced-support settings. The weighting is chosen precisely so that the binary-component extraction commutes with the transform even when q is composite; we will include a brief remark confirming that no support restrictions are required. revision: yes
Circularity Check
No significant circularity; definitions are independent
full rationale
The paper introduces the root-Hadamard transform by explicit definition on generalized Boolean functions f : Z_2^n → Z_q and then describes its action on binary components. Complementarity is likewise defined directly in the spirit of Golay sequences. No load-bearing step reduces a claimed prediction or uniqueness result to a fitted parameter, a self-citation chain, or an ansatz smuggled from prior work by the same authors. The derivation consists of new definitions followed by derived properties; it is self-contained against external benchmarks and receives the default non-circularity finding.
Axiom & Free-Parameter Ledger
Reference graph
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