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arxiv: 2606.05044 · v1 · pith:FEU63S22new · submitted 2026-06-03 · 🪐 quant-ph

Generalized Bicycle Codes as Cyclic Submodules and their Automorphism Structure

Pith reviewed 2026-06-28 05:39 UTC · model grok-4.3

classification 🪐 quant-ph
keywords generalized bicycle codesquantum code automorphismsfold-transversal gatesClifford groupcyclic submodulespolynomial ringsquantum error correction
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The pith

Generalized bicycle codes expressed as cyclic submodules of R_ℓ² turn automorphism search into an algebraic problem on the ring.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper links the polynomial ring, parity-check matrix, and qubit space through a three-space dependency that lets generalized bicycle codes be written as pairs of cyclic submodules of R_ℓ². This representation converts the search for automorphisms into deterministic conditions on the ring, giving necessary and sufficient criteria for block-separable automorphisms built from cyclic shifts, ring automorphisms, and block swaps. The same conditions supply explicit tests for the existence of H-, S-, and CX-type fold-transversal gates and for the logical action produced by any such automorphism. The authors then construct the MCR family of codes that deliberately maximizes these algebraic features, yielding explicit k=2 examples up to distance 13 that generate the full 2-qubit Clifford group.

Core claim

By deriving a three-space dependency between the polynomial ring space, the parity check matrix space, and the F₂^{2ℓ} qubit space, GB codes are expressed as a pair of cyclic submodules of R_ℓ² ≅ F₂[x]/(x^ℓ−1). This reduces the search for code automorphisms to a deterministic algebraic problem, deriving necessary and sufficient conditions for the existence of block-separable automorphisms built from cyclic shifts, ring automorphisms and block-swaps. These conditions connect to the fold-transversal gate framework, providing explicit criteria for the existence of H-, S-, and CX-type fold-transversal gates. The MCR family is introduced to maximize automorphism flexibility, with k=2 codes up to

What carries the argument

The representation of a GB code as a pair of cyclic submodules of R_ℓ², which converts automorphism questions into algebraic conditions on the ring.

If this is right

  • Block-separable automorphisms exist if and only if the corresponding ring conditions hold.
  • Explicit algebraic criteria decide the existence of H-, S-, and CX-type fold-transversal gates.
  • Structured bases for logical operators determine the logical action realized by any automorphism.
  • The MCR family produces k=2 codes up to distance 13 that generate the full 2-qubit Clifford group.
  • k>2 MCR codes yield at least 20 distinct logical gates from automorphisms alone.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same submodule representation could be used to engineer codes whose automorphism groups realize other finite gate sets beyond the Clifford group.
  • Because the construction rests on classical cyclic-code ideas, the method may extend to other CSS or quasi-cyclic quantum codes.
  • Inverse design becomes feasible: one can search the ring for submodule pairs that simultaneously satisfy distance and desired automorphism properties.
  • The algebraic criteria supply a decidable test that could be automated to enumerate all low-weight GB codes with nontrivial logical gates.

Load-bearing premise

Generalized bicycle codes admit a three-space dependency that allows them to be expressed as cyclic submodules of R_ℓ² in a manner that directly reduces automorphism search to algebraic conditions on the ring.

What would settle it

A concrete GB code whose automorphism group contains an element that cannot be obtained from any combination of cyclic shifts, ring automorphisms, and block swaps satisfying the derived ring conditions, or an MCR code whose combined automorphism and fold-transversal gates fail to produce all elements of the 2-qubit Clifford group.

Figures

Figures reproduced from arXiv: 2606.05044 by AJ Davenport, Isaac Chuang, John Blue.

Figure 1
Figure 1. Figure 1: The three-space framework for Generalized Bicycle codes. The historical approach (dashed line) attempts to find physical qubit permutations that preserve the global matrix rowspaces, an opaque and computationally heavy search outside of the trivial cyclic shift solutions (recently improved by [19], however does not provide insight into why automorphisms arise). The fundamental insight of this work (double … view at source ↗
Figure 2
Figure 2. Figure 2: The classical three-space dependency at ℓ = 7: the element x + x 4 + x 5 ∈ R7 and its equivalent representations as a binary circulant matrix in circ(F 7×7 2 ) and a vector in F 7 2. Each row of the circulant is the coefficient vector of x i · a(x) mod (x 7 + 1). representations of f1, f2, mapping f1 to A, and f2 to B: HX = [A|B] HZ = [B T |A T ] (2) Note that by the isomorphism above for classical codes, … view at source ↗
Figure 3
Figure 3. Figure 3: Algebraic decomposition of a Generalized Bicycle (GB) code into its cyclic submodule structure. A GB code is defined by parameters (ℓ, f1, f2) with f1, f2 ∈ Rℓ (green, Polynomial Ring Space). Writing f = gcd(f1, f2, xℓ − 1) extracts the shared factor and yields transfer polynomials p, q satisfying f1 = pf, f2 = qf. The shared ideal ⟨f⟩ is then split by p and q into left and right images, which combine into… view at source ↗
Figure 4
Figure 4. Figure 4: The quantum three-space equivalence for a GB code with ℓ = 5, f = 1 + x, p = x 3 , q = 1 + x + x 3 . A single stabilizer generator (pf, qf) ∈ R 2 5 maps to the first row of HX in the matrix space. In the physical qubit space (C 2 ) ⊗10, that row’s coefficient vector (0, 0, 0, 1, 1 | 1, 0, 1, 1, 1) encodes a Pauli-X generator SX = IIIXX | XIXXX (Pauli layer); the full stabilizer group S generated by all suc… view at source ↗
Figure 5
Figure 5. Figure 5: Proposition 3.2 as a three-space classification of block-separable automorphisms. The rowspaces rs(HX) and rs(HZ ) belong to the Matrix Space, while the left/right block decomposition belongs to the Physical Qubit Space. Two ring-level maps ψL, ψR on Rℓ, applied to each half and optionally composed with the full block swap σ, produces four cases organized by two independent binary choices: whether ϕ is blo… view at source ↗
Figure 6
Figure 6. Figure 6: Illustration of Theorem 3.4. A graphical depiction of the four possible block-separable M∼ automorphisms induced by a substitution multiplier ψxj . Depending on how the multiplier transforms the transfer polynomials p and q within the quotient ring S, the induced physical qubit permutation ϕ either acts blockwise independently (ψxj ⊕ ψxj ) or must be composed with the full block swap σ to preserve the unde… view at source ↗
Figure 7
Figure 7. Figure 7: Visualization of Theorem 3.10: Fold-Transversal CNOTs and M¨obius-like Repair (CNOT2→1, M∼ case) A physical CNOT disrupts the cyclic submodule structure by modifying one of the coordinates out of the target ideal. Following the CNOT with a ring multiplier permutation ψxj ⊕ ψxj can restore the structure (mapping the pair back into rs(HX) or rs(HZ )) if the transfer polynomials satisfy a specific M¨obius-lik… view at source ↗
Figure 8
Figure 8. Figure 8: Guided search algorithm for code automorphisms and fold-transversal gates in GB codes ( [PITH_FULL_IMAGE:figures/full_fig_p028_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Conceptual logic behind Theorem 4.3, which establishes a canonical F2-basis for the X-type logical operators of a GB code. Writing ℓ = 2sm with m odd and di = deg(fi), let ζi = vi(f), ρi = vi(p), σi = vi(q) denote the fi-adic valuations of f, p, q. The argument proceeds by (1) CRT-decomposing Rℓ into local chain rings Li, (2) restating the component kernel Ki and stabilizer Si conditions, (3) reparameteriz… view at source ↗
read the original abstract

Automorphisms of quantum codes, when they exist, offer a pathway toward fault-tolerant gate implementation via qubit relabeling. Although useful, the conditions under which automorphisms appear in a given code remain poorly understood. In this paper, we develop an algebraic framework for systematically analyzing and engineering automorphisms in Generalized Bicycle (GB) codes. Central to our approach is the derivation of a three-space dependency between the polynomial ring space, the parity check matrix space, and the $\mathbb{F}_2^{2\ell}$ qubit space, similar to the structure found in the study of classical cyclic codes. By expressing GB codes as a pair of cyclic submodules of $R_\ell^2$, where $R_\ell \cong \mathbb{F}_2[x]/\langle x^\ell-1\rangle$, we reduce the search for code automorphisms to a deterministic algebraic problem, deriving necessary and sufficient conditions for the existence of block-separable automorphisms built from cyclic shifts, ring automorphisms and block-swaps. We connect these conditions to the fold-transversal gate framework, providing explicit criteria for the existence of $H$-, $S$-, and $CX$-type fold-transversal gates. We further discuss structured bases for logical operators in order to determine the logical action of a given automorphism. Finally, we introduce the Maximal Cube Root (MCR) code family, a family of GB codes constructed around the principle of maximizing automorphism flexibility and fold-CX gates. We demonstrate a collection of $k=2$ MCR codes up to $d=13$ generating the 2-qubit Clifford group via automorphism and fold-transversal gates, with stabilizer weight ranging from 8 to 16, and $k>2$ MCR codes with a minimum of 20 distinct logical gates achievable from automorphisms. This serves as a first demonstration of inverse design: using these methods to build codes around a rich automorphism structure from the ground up.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 2 minor

Summary. The manuscript develops an algebraic framework for Generalized Bicycle (GB) codes by deriving a three-space dependency between the polynomial ring, parity-check matrix, and qubit space, expressing GB codes as a pair of cyclic submodules of R_ℓ² ≅ F₂[x]/(x^ℓ−1). It reduces automorphism search to algebraic conditions on the ring and derives necessary and sufficient conditions for block-separable automorphisms (cyclic shifts, ring automorphisms, block-swaps). The work connects these to explicit criteria for fold-transversal H-, S-, and CX-type gates, discusses structured bases for logical operators, and introduces the Maximal Cube Root (MCR) code family. Explicit k=2 MCR constructions up to d=13 are shown to generate the 2-qubit Clifford group via automorphisms and fold-transversal gates (stabilizer weights 8–16), along with k>2 examples achieving at least 20 distinct logical gates.

Significance. If the algebraic modeling and derivations hold, the paper provides a systematic, ring-theoretic method for engineering quantum codes with prescribed automorphism groups, enabling inverse design for fault-tolerant gates. The reduction of automorphism existence to deterministic algebraic conditions on R_ℓ and the explicit MCR constructions that realize the full 2-qubit Clifford group constitute a concrete advance, offering falsifiable examples with moderate stabilizer weights.

major comments (1)
  1. [Abstract / introduction (three-space dependency)] The three-space dependency (abstract, paragraph beginning 'Central to our approach') is load-bearing for the central claim that GB codes can be expressed as cyclic submodules of R_ℓ² and that this directly yields necessary and sufficient conditions on the ring. The manuscript should include an explicit derivation or proposition showing that the GB parity-check matrix structure induces the submodule property for arbitrary defining polynomials without hidden constraints.
minor comments (2)
  1. The abstract states that 'necessary and sufficient conditions' are derived; the main text should cross-reference the specific theorem or proposition numbers where these conditions appear.
  2. [MCR code family] In the MCR code family section, the design principle of 'maximizing automorphism flexibility' should be stated more formally (e.g., as an optimization over the ring elements) to facilitate reproducibility of the constructions.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their positive assessment and recommendation of minor revision. We address the single major comment below.

read point-by-point responses
  1. Referee: [Abstract / introduction (three-space dependency)] The three-space dependency (abstract, paragraph beginning 'Central to our approach') is load-bearing for the central claim that GB codes can be expressed as cyclic submodules of R_ℓ² and that this directly yields necessary and sufficient conditions on the ring. The manuscript should include an explicit derivation or proposition showing that the GB parity-check matrix structure induces the submodule property for arbitrary defining polynomials without hidden constraints.

    Authors: We agree that an explicit derivation strengthens the central claim. In the revised manuscript we will add a new Proposition (placed immediately after the GB code definition) that starts from the parity-check matrix in polynomial form H = [a(x) | b(x)] and derives the three-space dependency. The proof shows that the code is the intersection of two cyclic submodules of R_ℓ² for arbitrary a(x), b(x) ∈ R_ℓ, with no additional constraints on the defining polynomials; it explicitly maps the row space of H to the submodule generators and verifies closure under multiplication by x. revision: yes

Circularity Check

0 steps flagged

No significant circularity detected

full rationale

The paper's central contribution is a modeling choice that expresses GB codes as cyclic submodules of R_ℓ², followed by algebraic derivation of automorphism conditions from that representation. This is a standard extension of classical cyclic-code techniques to the quantum setting and does not reduce any claimed result to a fitted parameter, self-referential definition, or load-bearing self-citation. The MCR family is explicitly constructed around stated design goals rather than reverse-engineered from target outcomes, and the Clifford-group demonstration follows directly from the derived algebraic criteria. No load-bearing step collapses to its own inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 1 invented entities

The approach rests on the domain assumption that GB codes admit the stated three-space cyclic-submodule representation; the MCR family is an invented construction whose independent evidence is the explicit examples claimed in the abstract.

axioms (1)
  • domain assumption GB codes admit a three-space dependency between the polynomial ring space, the parity-check matrix space, and the F₂^{2ℓ} qubit space that permits representation as cyclic submodules of R_ℓ²
    Invoked as 'Central to our approach' in the abstract; this modeling choice enables the entire algebraic reduction.
invented entities (1)
  • Maximal Cube Root (MCR) code family no independent evidence
    purpose: Family of GB codes constructed to maximize automorphism flexibility and fold-CX gates
    Introduced in the abstract as a new construction principle; no external evidence supplied.

pith-pipeline@v0.9.1-grok · 5887 in / 1682 out tokens · 27507 ms · 2026-06-28T05:39:00.730297+00:00 · methodology

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Reference graph

Works this paper leans on

52 extracted references · 12 canonical work pages

  1. [1]

    Jean-Pierre Tillich and Gilles Zemor. Quantum LDPC Codes With Positive Rate and Min- imum Distance Proportional to the Square Root of the Blocklength.IEEE Transactions on Information Theory, 60(2):1193–1202, February 2014. URLhttp://dx.doi.org/10.1109/ TIT.2013.2292061

  2. [2]

    In Victor V

    Hypergraph product (HGP) code. In Victor V. Albert and Philippe Faist, editors,The Error Correction Zoo. 2024. URLhttps://errorcorrectionzoo.org/c/hypergraph_product

  3. [3]

    Asymptotically good Quantum and locally testable classical LDPC codes

    Pavel Panteleev and Gleb Kalachev. Asymptotically good Quantum and locally testable classical LDPC codes. InProceedings of the 54th Annual ACM SIGACT Symposium on Theory of Computing, STOC 2022, pages 375–388, New York, NY, USA, 2022. Association for Computing Machinery. URLhttps://dl.acm.org/doi/10.1145/3519935.3520017

  4. [4]

    Pablo Bonilla Ataides, Christopher A

    Qian Xu, J. Pablo Bonilla Ataides, Christopher A. Pattison, Nithin Raveendran, Dolev Bluvstein, Jonathan Wurtz, Bane Vasi´ c, Mikhail D. Lukin, Liang Jiang, and Hengyun Zhou. Constant-overhead fault-tolerant quantum computation with reconfigurable atom ar- rays.Nature Physics, 20(7):1084–1090, 2024. URLhttps://www.nature.com/articles/ s41567-024-02479-z

  5. [5]

    Breuckmann and Jens N

    Nikolas P. Breuckmann and Jens N. Eberhardt. Balanced Product Quantum Codes.IEEE Transactions on Information Theory, 67(10):6653–6674, October 2021. URLhttps:// ieeexplore.ieee.org/document/9490244/. 50

  6. [6]

    Cross, Jay M

    Sergey Bravyi, Andrew W. Cross, Jay M. Gambetta, Dmitri Maslov, Patrick Rall, and Theodore J. Yoder. High-threshold and low-overhead fault-tolerant quantum mem- ory.Nature, 627(8005):778–782, March 2024. URLhttps://www.nature.com/articles/ s41586-024-07107-7

  7. [7]

    Towards Ultra- High-Rate Quantum Error Correction with Reconfigurable Atom Arrays, 2026

    Chen Zhao, Casey Duckering, Andi Gu, Nishad Maskara, and Hengyun Zhou. Towards Ultra- High-Rate Quantum Error Correction with Reconfigurable Atom Arrays, 2026. URLhttps: //arxiv.org/abs/2604.16209

  8. [8]

    Breaking the Orthogonality Barrier in Quantum LDPC Codes, 2026

    Kenta Kasai. Breaking the Orthogonality Barrier in Quantum LDPC Codes, 2026. URL https://arxiv.org/abs/2601.08824

  9. [9]

    Leveraging automorphisms of quantum codes for fault- tolerant quantum computation

    Markus Grassl and Martin Roetteler. Leveraging automorphisms of quantum codes for fault- tolerant quantum computation. In2013 IEEE International Symposium on Information The- ory, pages 534–538, 2013. URLhttps://ieeexplore.ieee.org/document/6620283

  10. [10]

    Breuckmann and Simon Burton

    Nikolas P. Breuckmann and Simon Burton. Fold-Transversal Clifford Gates for Quan- tum Codes.Quantum, 8:1372, June 2024. URLhttps://quantum-journal.org/papers/ q-2024-06-13-1372/

  11. [11]

    Ex- tractors: QLDPC Architectures for Efficient Pauli-Based Computation.arXiv preprint arXiv:2503.10390, 2025

    Zhiyang He, Alexander Cowtan, Dominic J Williamson, and Theodore J Yoder. Ex- tractors: QLDPC Architectures for Efficient Pauli-Based Computation.arXiv preprint arXiv:2503.10390, 2025. URLhttps://arxiv.org/abs/2503.10390

  12. [12]

    Yoder, Eddie Schoute, Patrick Rall, Emily Pritchett, Jay M

    Theodore J. Yoder, Eddie Schoute, Patrick Rall, Emily Pritchett, Jay M. Gambetta, An- drew W. Cross, Malcolm Carroll, and Michael E. Beverland. Tour de gross: A modular quantum computer based on bivariate bicycle codes, 2025. URLhttps://arxiv.org/abs/ 2506.03094

  13. [13]

    Wilson, Jon Gorchon, Charles-Henri Lambert, Sayeef Salahuddin, and Jeffrey Bokor

    Lawrence Z. Cohen, Isaac H. Kim, Stephen D. Bartlett, and Benjamin J. Brown. Low- overhead fault-tolerant quantum computing using long-range connectivity.Science Advances, 8(20), May 2022. ISSN 2375-2548. URLhttps://www.science.org/doi/10.1126/sciadv. abn1717

  14. [14]

    Improved QLDPC Surgery: Logical Measurements and Bridging Codes.arXiv preprint arXiv:2407.18393, 2024

    Andrew Cross, Zhiyang He, Patrick Rall, and Theodore Yoder. Improved QLDPC Surgery: Logical Measurements and Bridging Codes.arXiv preprint arXiv:2407.18393, 2024. URL https://arxiv.org/abs/2407.18393

  15. [15]

    Williamson and Theodore J

    Dominic J. Williamson and Theodore J. Yoder. Low-overhead fault-tolerant quantum com- putation by gauging logical operators.Nature Physics, 22(4):598–603, 2026. URLhttps: //www.nature.com/articles/s41567-026-03220-8

  16. [16]

    Gowda, Priya J

    Benjamin Ide, Manoj G. Gowda, Priya J. Nadkarni, and Guillaume Dauphinais. Fault- Tolerant Logical Measurements via Homological Measurement.Physical Review X, 15(2), June

  17. [17]

    URLhttps://journals.aps.org/prx/abstract/10.1103/PhysRevX.15.021088

  18. [18]

    Esha Swaroop, Tomas Jochym-O’Connor, and Theodore J. Yoder. Universal Adapters between Quantum Low-Density Parity Check Codes.PRX Quantum, 7(1), 2026. URLhttps:// journals.aps.org/prxquantum/abstract/10.1103/1g44-jp62

  19. [19]

    Yuan, Alexander Cowtan, Zhiyang He, Ting-Chun Lin, and Dominic J

    Andrew C. Yuan, Alexander Cowtan, Zhiyang He, Ting-Chun Lin, and Dominic J. Williamson. Parsimonious Quantum Low-Density Parity-Check Code Surgery, 2026. URLhttps:// arxiv.org/abs/2603.05082

  20. [20]

    Hasan Sayginel, Stergios Koutsioumpas, Mark Webster, Abhishek Rajput, and Dan E. Browne. Fault-tolerant logical clifford gates from code automorphisms.PRX Quantum, 6: 030343, Sep 2025. URLhttps://link.aps.org/doi/10.1103/vf7v-cpq9

  21. [21]

    Diaconu, Daniel Bochen Tan, Alexandra A

    Jin Ming Koh, Anqi Gong, Andrei C. Diaconu, Daniel Bochen Tan, Alexandra A. Geim, Michael J. Gullans, Norman Y. Yao, Mikhail D. Lukin, and Shayan Majidy. Entangling logical qubits without physical operations, 2026. URLhttps://arxiv.org/abs/2601.20927

  22. [22]

    Exhaustive Optimisation of Automorphism Groups for Stabiliser Codes, 2026

    Aisling Mac Aree and Mark Howard. Exhaustive Optimisation of Automorphism Groups for Stabiliser Codes, 2026. URLhttps://arxiv.org/abs/2604.01282

  23. [23]

    Logical Operators and Fold-Transversal Gates of Bivariate Bicycle Codes, 2024

    Jens Niklas Eberhardt and Vincent Steffan. Logical Operators and Fold-Transversal Gates of Bivariate Bicycle Codes, 2024. URLhttps://arxiv.org/abs/2407.03973

  24. [24]

    Gullans, Yifan Hong, Maryam Mudassar, and Shi Jie Samuel Tan

    Noah Berthusen, Michael J. Gullans, Yifan Hong, Maryam Mudassar, and Shi Jie Samuel Tan. Automorphism gadgets in homological product codes, 2025. URLhttps://arxiv.org/ abs/2508.04794

  25. [25]

    Simple logical quantum computation with concate- nated symplectic double codes, 2025

    Noah Berthusen and Elijah Durso-Sabina. Simple logical quantum computation with concate- nated symplectic double codes, 2025. URLhttps://arxiv.org/abs/2510.18753. 51

  26. [26]

    Degenerate Quantum LDPC Codes With Good Finite Length Performance.Quantum, 5:585, November 2021

    Pavel Panteleev and Gleb Kalachev. Degenerate Quantum LDPC Codes With Good Finite Length Performance.Quantum, 5:585, November 2021. URLhttps://quantum-journal. org/papers/q-2021-11-22-585/pdf/

  27. [27]

    Renyu Wang and Leonid P. Pryadko. Distance bounds for generalized bicycle codes, 2022. URLhttps://arxiv.org/abs/2203.17216

  28. [28]

    Kovalev and Leonid P

    Alexey A. Kovalev and Leonid P. Pryadko. Quantum Kronecker sum-product low-density parity-check codes with finite rate.Physical Review A, 88(1):012311, July 2013. URLhttps: //link.aps.org/doi/10.1103/PhysRevA.88.012311

  29. [29]

    Cary Huffman and Vera Pless.Fundamentals of Error-Correcting Codes

    W. Cary Huffman and Vera Pless.Fundamentals of Error-Correcting Codes. Cambridge University Press, Cambridge, UK, 2003. ISBN 9780521782807

  30. [30]

    Dummit and R.M

    D.S. Dummit and R.M. Foote.Abstract Algebra. Wiley, 2003. ISBN 9780471433347

  31. [31]

    Quantum LDPC Codes With Almost Linear Minimum Distance.IEEE Transactions on Information Theory, 68(1):213–229, January 2022

    Pavel Panteleev and Gleb Kalachev. Quantum LDPC Codes With Almost Linear Minimum Distance.IEEE Transactions on Information Theory, 68(1):213–229, January 2022. URL https://ieeexplore.ieee.org/document/9567703

  32. [32]

    Quasicyclic codes of indexℓoverFq viewed asFq[x]-submodules ofFqℓ[x]/⟨xm− 1⟩.LCNS: Applied algebra, algebraic algorithms and error-correcting codes, 2643:244–253,

    Kristine Lally. Quasicyclic codes of indexℓoverFq viewed asFq[x]-submodules ofFqℓ[x]/⟨xm− 1⟩.LCNS: Applied algebra, algebraic algorithms and error-correcting codes, 2643:244–253,

  33. [33]

    URLhttps://link.springer.com/chapter/10.1007/3-540-44828-4_26

  34. [34]

    Dzhumadil’daev, and San Ling

    Kanat Abdukhalikov, Askar S. Dzhumadil’daev, and San Ling. Quasi-cyclic codes of index 2.Discrete Mathematics, 349(6):115004, June 2026. URLhttps://arxiv.org/abs/2504. 00568

  35. [35]

    Polynomial representation of additive cyclic codes and new quantum codes.Adv

    Reza Dastbasteh and Khalil Shivji. Polynomial representation of additive cyclic codes and new quantum codes.Adv. Math. Commun., 19:49–68, 2023. URLhttps://api. semanticscholar.org/CorpusID:255372576

  36. [36]

    Mart´ ınez-Moro, A

    E. Mart´ ınez-Moro, A. Pi˜ nera Nicol´ as, and I.F. R´ ua. Codes over affine algebras with a finite commutative chain coefficient ring.Finite Fields Appl., 49(C):94–107, January 2018. URL https://dl.acm.org/doi/10.1016/j.ffa.2017.09.008

  37. [37]

    Norton and Ana S˘ al˘ agean

    Graham H. Norton and Ana S˘ al˘ agean. On the Structure of Linear and Cyclic Codes over a Finite Chain Ring.Applicable Algebra in Engineering, Communication and Computing, 10 (6):489–506, 2000. URLhttps://link.springer.com/article/10.1007/PL00012382

  38. [38]

    Lopez-Permouth

    Hai Quang Dinh and S.R. Lopez-Permouth. Cyclic and negacyclic codes over finite chain rings.IEEE Transactions on Information Theory, 50(8):1728–1744, 2004. URLhttps:// ieeexplore.ieee.org/document/1317117

  39. [39]

    PhD thesis, California In- stitute of Technology, Pasadena, California, 1997

    Daniel Gottesman.Stabilizer Codes and Quantum Error Correction. PhD thesis, California In- stitute of Technology, Pasadena, California, 1997. URLhttps://arxiv.org/abs/quant-ph/ 9705052

  40. [40]

    Conway and Neil J

    John H. Conway and Neil J. A. Sloane.Sphere Packings, Lattices and Groups, volume 290 ofGrundlehren der mathematischen Wissenschaften. Springer-Verlag, New York, 3 edition,

  41. [41]

    ISBN 978-0-387-98585-5

  42. [42]

    The use of information sets in decoding cyclic codes.IRE Transactions on Information Theory, 8(5):5–9, 1962

    Eugene Prange. The use of information sets in decoding cyclic codes.IRE Transactions on Information Theory, 8(5):5–9, 1962. URLhttps://ieeexplore.ieee.org/document/ 1057777

  43. [43]

    Gurobi Optimizer Reference Manual, 2026

    Gurobi Optimization, LLC. Gurobi Optimizer Reference Manual, 2026. URLhttps://www. gurobi.com

  44. [44]

    SubMIT: A physics analysis facility at MIT, 2025

    Josh Bendavid, Mariarosaria D’Alfonso, Jan Eysermans, Chad Freer, Maxim Goncharov, Matthew Heine, Luca Lavezzo, Marianne Moore, Christoph Paus, Xuejian Shen, David Walter, and Zhangqier Wang. SubMIT: A physics analysis facility at MIT, 2025. URL https://arxiv.org/abs/2506.01958

  45. [45]

    The Automorphism Groups of BCH Codes and of Some Affine-Invariant Codes Over Extension Fields.Designs, Codes and Cryptography, 18:29–53, December 1999

    Thierry Berger and Pascale Charpin. The Automorphism Groups of BCH Codes and of Some Affine-Invariant Codes Over Extension Fields.Designs, Codes and Cryptography, 18:29–53, December 1999. URLhttps://dl.acm.org/doi/abs/10.1023/A%3A1008372800005

  46. [46]

    Tao Feng, Henk D. L. Hollmann, Weicong Li, and Qing Xiang. The permutation automorphism groups of irreducible cyclic codes, 2026. URLhttps://arxiv.org/abs/2603.01904

  47. [47]

    P. P. P´ alfy. Isomorphism problem for relational structures with a cyclic automorphism.Euro- pean Journal of Combinatorics, 8(1):35–43, 1987. URLhttps://www.sciencedirect.com/ science/article/pii/S0195669887800185. 52

  48. [48]

    W. C. Huffman, V. Job, and V. Pless. Multipliers and generalized multipliers of cyclic objects and cyclic codes.Journal of Combinatorial Theory, Series A, 62(2):183–215, 1993. URL https://dl.acm.org/doi/10.1016/0097-3165%2893%2990043-8

  49. [49]

    The permutation groups and the equivalence of cyclic and quasi-cyclic codes

    Kenza Guenda. The permutation groups and the equivalence of cyclic and quasi-cyclic codes. arXiv preprint, 2010. URLhttps://arxiv.org/abs/1002.2456

  50. [50]

    Main usage

    Reza Dastbasteh and Petr Lisonˇ ek. On the equivalence of linear cyclic and constacyclic codes. Discrete Math., 346(9), September 2023. URLhttps://dl.acm.org/doi/10.1016/j.disc. 2023.113489. A List of Symbols The tables below collect the principal symbols used throughout the paper, organized according to the three-space dependency framework introduced in ...

  51. [51]

    There exists a proper divisord|ℓ,d<ℓ, such thatψd(c) =c∀c∈C, i.e., cyclically shifting bydpositions returns every codeword back to itself ford<ℓ

  52. [52]

    ˆg|xd−1 ford|ℓ, d<ℓ Non-trivial exceptions toPAut(C) =Z/ℓZ ⋊M(C)include the punctured Reed–Muller codes and the binary Golay code, withPAut(C) =M 23. It is a longstanding conjecture by Berger and Charpin [42], recently confirmed for irreducible cyclic codes [43], that for almost all cyclic codes the permutation automorphism group coincides with the affine...