REVIEW 2 major objections 9 minor 42 references
On de Bruijn Array Codes Part II: Linear Codes
T0 review · 2 major / 9 minor · reviewed 2026-08-10 · deepseek-v4-flash
Pith's one-line read This paper proves that folding the sequences of the root-product polynomial of two equal-period polynomials produces pseudo-random array codes with parameter sets not known before.
desk verdict Solid new constructions for pseudo-random array codes; the core proofs are sound, but the abstract overreaches and the key order argument in Corollary 29 should be made explicit. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The load-bearing object is the root-product polynomial $f_1\vee f_2$, defined as $\prod_{i,j}(x-\alpha_i\beta_j)$ over roots $\alpha_i$ of $f_1$ and $\beta_j$ of $f_2$; Proposition 27 identifies the set of sequences it generates with the linear span of bitwise products of sequences from $f_1$ and $f_2$. Around it stand two older mechanisms: the zero factor, a set of cyclic sequences of common least period containing each nonzero $n$-tuple exactly once, and folding, which writes a sequence of length $r_1r_2$ into an $r_1\times r_2$ toroidal array along the diagonal using the Chinese Remainder Theorem. The paper's two verification tools are the set polynomial $g_P(x)=\prod_{Q\subseteq P}\sum_{p_i\in Q}x^{p_i}$, whose non-divisibility by an irreducible polynomial decides whether the projected coordinates contain every nonzero tuple, and, for products of irreducible factors, an $n_1n_2\times n_1n_2$ binary matrix $C$ whose non-zero determinant decides the same question.
What would settle it
Enumerate all sequences generated by the polynomial $f_1\vee f_2$ in Example 14 (degree 24, exponent 45), fold them into $5\times 9$ arrays, and check whether every one of the $2^{24}-1$ nonzero $4\times 6$ matrices appears exactly once as a window; a duplicate or missing window would disprove Corollary 29, while the same check on the six degree-12 exponent-91 sequences of Example 11 would test Theorem 30.
Extended reading notes
Core claim
On the paper's own terms, the central discovery is that folding is more flexible than the classical construction assumed. Theorem 28 states: for coprime $r_1,r_2$, if $f_1$ and $f_2$ are non-constant binary polynomials of degrees $n_1,n_2$ whose nonzero sequences all have least periods $r_1,r_2$ respectively, and $g(x)=f_1(x)\vee f_2(x)$ (the polynomial whose roots are all products $\alpha\beta$ of roots of $f_1$ and $f_2$) has degree $n_1n_2$ and uniform exponent $r_1r_2$, then folding the sequences generated by $g$ into $r_1\times r_2$ arrays yields an $(r_1,r_2;n_1,n_2)$-pseudo-random array code. Corollary 29 asserts that folding always succeeds under those hypotheses, and Theorem 30 proves the analogous statement for one irreducible polynomial of degree $n_1n_2$ and exponent $r_1r_2$ whenever $r_1$ divides $2^{n_1}-1$ and $2^0,\dots,2^{n_1-1}$ are distinct modulo $r_1$. The proof shows each array column is a sequence from $f_1$ and each row a sequence from $f_2$, so the all-zero window cannot occur and any two equal windows would force one by the shift-and-add property.
Load-bearing premise
The construction assumes that the product map on roots—taking a root $\alpha$ of $f_1$ and a root $\beta$ of $f_2$ to $\alpha\beta$—never collides, so that $f_1\vee f_2$ really has degree $n_1n_2$ and every nonzero sequence it generates has period $r_1r_2$; if two distinct pairs gave the same product, some nonzero window would be missing from the folded code.
Editorial extensions
If this is right
- New parameter sets: Corollary 29 and Theorem 30 produce PRACs such as $(7,13;3,4)$, $(5,9;4,6)$, and $(7,15;6,8)$, parameters not obtained by the classical folding proof.
- Infinite families: when $\gcd(2^{n_1}-1,2^{n_2}-1)=1$ there is a $(2^{n_1}-1,2^{n_2}-1;n_1,n_2)$-PRAC; when $n_1+1$ and $n_2+1$ are distinct primes there is an $(n_1+1,n_2+1;n_1,n_2)$-PRAC.
- Every code produced this way has shift-and-add: adding two codewords, or a codeword and a nontrivial shift, gives another codeword, so together with the all-zero array the codewords form a linear array code.
- The two necessary-and-sufficient criteria let a user verify a candidate folding by one polynomial division or one determinant, rather than by exhaustive window search.
- The construction hierarchy: when $g(x)$ is irreducible, the Corollary 29 construction is also covered by Theorem 30; the genuinely new codes are the reducible-$g$ codes and the Theorem 30 cases where $r_2$ does not divide $2^{n_2}-1$.
Reading between the lines
- The determinant test in Theorem 47 is algorithmically efficient, so it could be used to search exhaustively over polynomials of a given degree and exponent for foldings that form PRACs; the paper itself reports experimental evidence that more parameters exist than the theorems cover.
- The same root-product construction should transfer to non-binary alphabets whenever the analogous uniform-exponent and root-product injectivity conditions hold; the paper notes it treats only binary sequences and arrays, though some results generalize.
- Because the resulting array codes are linear, their minimum distance is a meaningful parameter for two-dimensional burst or criss-cross error correction; the paper flags minimum-distance analysis as future work.
- Conjecture 1, if true, would give a nesting hierarchy in which multiplying $k$ irreducible factors with the same exponent upgrades an $(r_1,r_2;n_1,n_2)$-PRAC to an $(r_1,r_2;n_1,kn_2)$-PRAC; the paper's Example 19 shows the condition $n_1<r_1<2^{n_1}$ is essential.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper studies binary shortened de Bruijn array codes with the shift-and-add property, called pseudo-random array codes (PRACs). It constructs PRACs by folding sequences generated by linear recurrences whose nonzero sequences all have the same period. The main results are Theorem 16, which relaxes the MacWilliams-Sloane conditions for folding an M-sequence into a pseudo-random array; Theorem 28 and Corollary 29, which construct a PRAC by folding the sequences of f1(x) ∨ f2(x) when f1 and f2 have coprime uniform exponents; Theorem 30, which constructs a PRAC from a single irreducible polynomial of degree n1n2 and exponent r1r2 under conditions on r1; and two necessary-and-sufficient verification criteria, Theorem 26 (via set polynomials) and Theorem 47 (via a determinant condition). The paper also contains a detailed case analysis of which combinations of primitive, irreducible non-primitive, and reducible polynomials can occur, several infinite families, and a conjecture about a hierarchy of PRACs.
Significance. If the results are correct, the paper makes a substantial contribution to the theory of two-dimensional pseudo-random arrays. Theorem 30 and Corollary 29 appear to yield parameter sets not previously available, such as (7,13;3,4) and (7,15;6,8), and the determinant criterion in Theorem 47 is a useful verification tool for reducible polynomials. The main proofs are based on standard finite-field techniques, and the linear-independence arguments in Theorems 16 and 30 are convincing. The paper also gives many explicit examples, which materially help the reader. The main weakness is that two load-bearing steps are asserted without proof: the degree and uniform-exponent claim for f1∨f2 in Corollary 29, and the exclusion of the all-zero window in the sufficiency direction of Theorem 47. Both are fixable by short arguments, but they need to be stated.
major comments (2)
- [Section IX, Theorem 47 and Corollary 48] The corollary asserts that f1(x) ∨ f2(x) has degree n1n2 and uniform exponent r1r2, but this is not proved. Proposition 27 only gives the identity S(f1)·S(f2) = S(f1∨f2), and Lemma 23 gives the least period r1r2 for nonzero sequences in that span; neither statement by itself implies that the root-product map (α,β) ↦ αβ is injective on the roots of f1 and f2, nor that every root of f1∨f2 has exact order r1r2. Without these facts the parameters of the zero factor used in Theorem 28 are not justified. The gap is easily filled: if αβ = α′β′ for roots α, α′ of f1 and β, β′ of f2, then α/α′ = β′/β has order dividing both r1 and r2, hence equals 1; similarly, if (αβ)^d = 1 with d dividing r1r2, then r1 | d and r2 | d, so the order is r1r2. This order argument should be included before Corollary 29.
- [Section IX, Theorem 47 and Corollary 48] The sufficiency direction proves that two foldings agreeing in an n1×n2 window must come from equal sequences, but it does not explicitly show that the all-zero n1×n2 matrix never appears as a window. Since an SDBAC has exactly 2^{n1n2}−1 windows to contain the nonzero matrices, the zero window must be excluded. The same linear-algebra argument does exclude it by taking the second sequence to be the zero sequence (σ′u = 0 for all u), so the fix is short, but this case is not stated in the proof and should be added.
minor comments (9)
- [Abstract] The sentence 'All the known arrays can be formed by folding sequences generated from an irreducible polynomial or a reducible polynomial whose factors have the same degree and the same exponent' is stated without proof or reference in the body; it should be removed or replaced by a supported statement about the constructions in this paper.
- [Definition 13] The set polynomial g_P(x) is defined as a product over all Q ⊆ P, including the empty set; the factor Σ_{p_i∈∅} x^{p_i} is 0, making g_P(x) identically zero. The product should be over nonempty subsets Q.
- [Definition 5] The phrase 'if A, B ∈ C (A and B are either distinct or B is a nontrivial shift of A)' is ambiguous about whether every shift of a codeword is itself a codeword; the following sentence about all cyclic shifts forming a linear code suggests the intended meaning, so the definition should be rephrased for clarity.
- [Corollary 48] The range '1 ≤ j < n2' in the list of vectors β^i γ^j should be '0 ≤ j < n2', since the proof and the dimension count use n1n2 vectors.
- [Theorem 47 proof] In the display computing the top-left window, the bounds '0 ≤ i < n1 − 1 and 0 ≤ j < n2 − 1' should be '0 ≤ i < n1 and 0 ≤ j < n2'.
- [Lemma 23] The statement begins 'Let S(f1(x)) and S(f1(x))' with f1 repeated; the second set should be S(f2(x)).
- [Example 8] For the 3×4 windows, the set P lists the coordinate 105 twice; one occurrence appears to be a typo for another coordinate.
- [Section X, item 3] The text refers to 'Experimental results' but no experimental data or tables are included in the paper; either provide the data or rephrase the item as a remark based on the examples.
- [Throughout] There are several typographical errors, including 'Propsition' after Corollary 3, 'ploynomial' in Example 9, and 'diffferent' in the proof of Theorem 28; a careful proofreading pass is recommended.
Circularity Check
No circularity: the central constructions rest on external finite-field theorems, and self-citations are non-load-bearing.
full rationale
The paper's central claims, Theorem 28, Corollary 29, and Theorem 30, are derived from external results: the Zierler-Mills product theorem as presented in Lidl-Niederreiter (Proposition 27), the MacWilliams-Sloane folding proof method, and standard finite-field/trace theory. The self-citations to the authors' Part I and to Etzion's book are used only for definitions, terminology, context, and supporting lemmas; they are not the load-bearing justification for the new PRAC constructions. The one implicit step, namely that g(x) = f1(x) ∨ f2(x) has degree n1n2 and uniform exponent r1r2 under gcd(r1,r2) = 1, is not assumed as the target result; it follows directly from the defining uniform-exponent assumptions via the elementary order argument that the root-product map is injective and that each root has exact order r1r2. No fitted parameter is renamed as a prediction, no known result is merely relabeled, and no uniqueness theorem imported from the authors is invoked to force the construction. The derivation chain is therefore self-contained with respect to its stated external assumptions, and no circular step is present.
Assumptions & free parameters
assumptions (6)
- standard math The degree of an irreducible polynomial with exponent e equals the multiplicative order of 2 modulo e, and all irreducible polynomials with a given exponent have the same degree.
- standard math Zierler-Mills theorem: S(f1) times S(f2) equals S(f1 ∨ f2) for polynomials without repeated roots that generate zero factors.
- domain assumption A polynomial generating a zero factor produces nonzero sequences with no run of n zeros.
- standard math With gcd(r1, r2) = 1, the congruences k ≡ i mod r1 and k ≡ j mod r2 have a unique solution modulo r1r2, and cyclic shifts of the folded sequence correspond to cyclic shifts of the array.
- standard math Lemma 33: if 2^n_i ≡ 1 mod r_i for i = 1, 2 and gcd(r1, r2) = 1, then 2^(n1n2/gcd(n1,n2)) ≡ 1 mod r1r2, and this exponent is minimal when the n_i are minimal.
- standard math Any sequence generated by an irreducible polynomial f_u of degree n can be written uniquely as i maps to t_u(sigma alpha_u^i) for a fixed non-trivial F2-linear map t_u and sigma in F_{2^n}.
Cite this review
Pith. "Pith review of On de Bruijn Array Codes Part II: Linear Codes." pith.science (2026). https://pith.science/paper/D52O42E4
@misc{pith2026250112124,
author = {Pith},
title = {Pith review of: On de Bruijn Array Codes Part II: Linear Codes},
year = {2026},
howpublished = {\url{https://pith.science/paper/D52O42E4}},
note = {Machine review of arXiv:2501.12124}
}
abstract
An M-sequence generated by a primitive polynomial has many interesting and desirable properties. A pseudo-random array is the two-dimensional generalization of an M-sequence. There are non-primitive polynomials all of whose non-zero sequences have the same period. These polynomials generate \emph{sets} of sequences with properties similar to M-sequences. In this paper, a two-dimensional generalization for such sequences is given. This generalization is for a pseudo-random array code, which is a set of $r_1 \times r_2$ arrays in which each $n_1 \times n_2$ nonzero matrix is contained exactly once as a window in one of the arrays. Moreover, these arrays have the shift-and-add property, i.e., the bitwise addition of two arrays (or a nontrivial shift of such arrays) is another array (or a shift of another array) from the code. All the known arrays can be formed by folding sequences generated from an irreducible polynomial or a reducible polynomial whose factors have the same degree and the same exponent. Two proof techniques are used to prove the constructions are indeed of pseudo-random array codes. The first technique is based on another method, different from folding, for constructing some of these arrays. The second technique is a generalization of a known proof technique. This generalization enables the construction of pseudo-random arrays with parameters not known before, and also provides a variety of pseudo-random array codes which cannot be generated by the first method. The two techniques also suggest two different hierarchies between pseudo-random array codes. Finally, two methods to verify whether a folding of sequences, generated by these polynomials, yields a pseudo-random array or a pseudo-random array code, will be presented.
Figures
Reference graph
Works this paper leans on
-
[1]
Z. B ARZILAI , D. C OOPERSMITH , AND A. L. R OSENBERG , Exhaustive generation of bit patterns with application to VLSI self-testing, IEEE Trans. on Computers, 32 (1983) 190–194
work page 1983
-
[2]
B LAUM AND J
M. B LAUM AND J. B RUCK , MDS array codes for correcting criss-cross errors, IEEE Trans. on Infor. Theory, 46 (2000) 1068–1077
2000
-
[3]
B LAUM , J
M. B LAUM , J. B RUCK , A. VARDY, Interleaving schemes for multidimensional cluster errors, IEEE Trans. on Infor. Theory, 44 (1998) 730–743
1998
-
[4]
M. B REITBACH , M. B OSSERT , V. Z YABLOV, V. S IDORENKO , Array codes correcting a two-dimensional cluster of errors, IEEE Trans. on Infor. Theory, 44 (1998) 2025–2031
work page 1998
-
[5]
J. D AI AND C.-K. R. C HUNG , Touchscreen everywhere: On transferring a normal planar surface to touch-sensitive display, IEEE Trans. Cybern., 44 (2014) 1383–1396
work page 2014
-
[6]
E TZION , Constructions for perfect maps and pseudo-random arrays, IEEE Trans
T. E TZION , Constructions for perfect maps and pseudo-random arrays, IEEE Trans. on Infor. Theory, 34 (1988) 1308–1316
work page 1988
-
[7]
E TZION , Sequence folding, lattice tiling, and multidimensional coding, IEEE Trans
T. E TZION , Sequence folding, lattice tiling, and multidimensional coding, IEEE Trans. on Infor. Theory, 57 (2011) 4383–4400
work page 2011
-
[8]
E TZION , Sequences and the de Bruijn Graph: Properties, Constructions, and Applications, London, UK; San Diego, US, Cambridge, US: Elsevier, 2024
T. E TZION , Sequences and the de Bruijn Graph: Properties, Constructions, and Applications, London, UK; San Diego, US, Cambridge, US: Elsevier, 2024
2024
Show all 42 references
-
[9]
E TZION , Pseudo-Random and de Bruijn Array Codes, IEEE Int
T. E TZION , Pseudo-Random and de Bruijn Array Codes, IEEE Int. Symp. on Inf. Theory (ISIT) , pp. 1742–1747, Athens, Greece, July 2024
2024
-
[10]
E TZION , On de Bruijn array codes, Part I: nonlinear codes, IEEE Trans
T. E TZION , On de Bruijn array codes, Part I: nonlinear codes, IEEE Trans. on Infor. Theory, 71 (2025) 1434–1449
2025
-
[11]
E TZION AND A
T. E TZION AND A. VARDY, Two-dimensional interleaving schemes with repetitions: Constructions and bounds, IEEE Trans. on Infor. Theory, 48 (2002) 428–457
2002
-
[12]
E TZION AND E
T. E TZION AND E. YAAKOBI , Error-correction of multidimensional bursts, IEEE Trans. on Infor. Theory, 55 (2009) 961–976
2009
-
[13]
G ENG , Structured-light 3D surface imaging: A tutorial, Adv
J. G ENG , Structured-light 3D surface imaging: A tutorial, Adv. Opt. Photon., 3 (2011) 128–160
2011
-
[14]
S. W. G OLOMB , Shift Register Sequences, San Francisco, CA: Holden Day, 1967; 2nd revised edition, Laguna Hills, CA: Aegean Park, 1980; 3rd revised edition, World Scientific, Singapore 2017
1967
-
[15]
G ORESKY AND A
M. G ORESKY AND A. K LAPPER , Algebraic Shift Register Sequences, Cambridge, UK: Cambridge Univ. Press, 2012
2012
-
[16]
S. R. G OTTESMAN AND E. E. F ENIMORE , New family of binary arrays for aperture imaging, Applied Optics, 28 (1989) 4344–4352
1989
-
[17]
H OLLMANN , Design of test sequences for VLSI self-testing using LFSR, IEEE Trans
H. H OLLMANN , Design of test sequences for VLSI self-testing using LFSR, IEEE Trans. on Infor. Theory, 36 (1990) 386–392
1990
-
[18]
K IYASU , H
S. K IYASU , H. H OSHINO , K. Y ANO , AND S. F UJIMURA , Measurement of the 3-D shape of specular polyhedrons using an M-array coded light source, IEEE Trans. on Instrum. and Meas., 44 (1995) 775–778
1995
-
[19]
L EMPEL AND M
A. L EMPEL AND M. C OHN , Design of universal test sequences, IEEE Trans. on Infor. Theory, 31 (1985) 10–17
1985
-
[20]
L IDL , AND H
R. L IDL , AND H. N IEDERREITER , Finite fields, Cambridge, UK: Cambridge Univ. Press, 1997
1997
-
[21]
H. L IN, L. NIE, AND Z. SONG , A single-shot structured light means by encoding both color and geometrical features,Pattern Recognition, 54 (2016) 178–189
2016
-
[22]
F. J. M ACWILLIAMS AND N. J. A. S LOANE , Pseudo-random sequences and arrays, Proceedings of the IEEE, 64 (1976) 1715–1729
1976
-
[23]
F. J. M ACWILLIAMS AND N. J. A. S LOANE , The Theory of Error-Correcting Codes, North-Holland, Amsterdam, 1977
1977
-
[24]
C. J. M ITCHELL , Aperiodic and semi-periodic perfect maps, IEEE Trans. on Infor. Theory, 41 (1995) 88–95. 28
1995
-
[25]
R. A. M ORANO , C. O ZTURK , R. C ONN , S. D UBIN , S. Z IETZ , AND J. N ISSANOV , Structured light using pseudorandom codes, IEEE Trans. on Pattern Analysis and Machine Intelligence, 20 (1998) 322–327
1998
-
[26]
N OMURA , H
T. N OMURA , H. M IYAKAWA, H. I MAI , AND A. F UKUDA , The theory of two-dimensional linear recurring arrays, IEEE Trans. on Infor. Theory, 18 (1972) 773–785
1972
-
[27]
P AGÈS , J
J. P AGÈS , J. S ALVI, C. C OLLEWET , AND J. F OREST , Optimised de Bruijn patterns for one-shot shape acquisition, Image and Vision Comput., 23 (2005) 707–720
2005
-
[28]
K. G. P ATERSON , Perfect maps, IEEE Trans. on Infor. Theory, 40 (1994) 743–753
1994
-
[29]
I. S. R EED AND R. M. S TEWART, Note on existence of perfect maps, IRE Trans. on Infor. Theory, 8 (1962) 10–12
1962
-
[30]
R. M. R OTH, Maximum-rank array codes and their application to crisscross error correction, IEEE Trans. on Infor. Theory, 37 (1991) 328–336
1991
-
[31]
R. A. R UEPPEL , Analysis and Design of Stream Ciphers, Belin, Germany: Springer-Verlag, 1986
1986
-
[32]
S ALVI, S
J. S ALVI, S. F ERNANDEZ , T. P RIBANIC , AND X. L LADO , A state of art in structured light patterns for surface profilometry, Pattern Recognition, 43 (2010) 2666–2680
2010
-
[33]
S ALVI, J
J. S ALVI, J. P AGÈS , AND J. B ATLLE , PATTERN CODIFICATION STRATEGIES IN STRUCTURED LIGHT SYSTEMS , P ATTERN RECOGNI - TION , 37 (2004) 827–849
2004
-
[34]
S CHWARTZ AND J
M. S CHWARTZ AND J. B RUCK , Constrained codes as networks of relations, IEEE Trans. on Infor. Theory, 54 (2008) 2179–2195
2008
-
[35]
E. S. S ELMER , Linear Recurrence relations over finite fields, Department of Mathematics, University of Bergen, Bergen, 1966
1966
-
[36]
S PANN, A two-dimensional correlation property of pseudo-random maximum-length sequences, Proceedings of the IEEE, 53 (1963) 2137
R. S PANN, A two-dimensional correlation property of pseudo-random maximum-length sequences, Proceedings of the IEEE, 53 (1963) 2137
1963
-
[37]
H. J. W. S POELDER , F. M. V OS, E. M. P ETRIU , AND F. C. A. G ROEN , Some aspects of pseudo random binary array-based surface characterization, IEEE Trans. on Instrum. and Meas., 49 (2000) 1331–1336
2000
-
[38]
S ZENTANDRÁSI , M
I. S ZENTANDRÁSI , M. Z ACHARIÁ ˘S, J. H AVEL, A. H EROUT , M. D UBSKÁ , AND R. K AJAN , Uniform marker fields: Camera localization by orientable de Bruijn tori, Proc. IEEE Int. Symp. Mixed Augmented Reality, (2012) 319–320
2012
-
[39]
I. T AL, T. E TZION , AND R. R OTH, On row-by-row coding for 2-D constraints, IEEE Trans. on Infor. Theory, 55 (2009) 3565–3576
2009
-
[40]
D. T. T ANG AND C. C HEN , Logic test-pattern generation using linear codes, IEEE Trans. Computers, 33 (1984) 845–850
1984
-
[41]
W ANG AND E
L.-T. W ANG AND E. J. M CCLUSKEY , Circuits for pseudoexhaustive test pattern generation, IEEE Trans. on Comput. Aided Design, 7 (1988) 1068–1080
1988
-
[42]
Z IERLER AND W
N. Z IERLER AND W. M. M ILLS , Products of linear recurring sequences, J, of Algebra, 27 (1973) 147–157
1973
Reviewed August 10, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.