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Claus Michael Ringel's main contributions to Gorenstein-projective modules

T0 review · 2 major / 5 minor · reviewed 2026-08-15 · deepseek-v4-flash

Pith's one-line read A survey of one mathematician's work claims that a six-dimensional algebra and the ℧-quiver settle the independence of the three total-reflexivity conditions and reshape the classification of Gorenstein-projective modules.

desk verdict A useful, honest survey of Ringel's Gorenstein-projective work with no new math, but the 'first complete solution' priority claim overreaches a private email and needs softening or a real prior-art check. read the letter →

arxiv 2505.12637 v1 pith:MNNDTFHP submitted 2025-05-19 math.RT

classification math.RT MSC 16G1013D0716E6516G50
keywords Gorenstein-projectivemodulessemi-Gorenstein-projectivetotalreflexivityconditions℧-quiverNakayamaalgebraspreprojectiveshortlocalKoszul
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This paper is a survey of one mathematician's body of work on Gorenstein-projective modules, and its organizing claim is that this work solved the independence problem for the three conditions originally used to define those modules. On the survey's telling, a six-dimensional local algebra yields modules satisfying any two of the conditions (G1), (G2), and (G3) while failing the third, so the conditions are genuinely independent for artin algebras. The same body of work contributes the ℧-quiver as a bookkeeping device for syzygy-like operations, a fast algorithm for Nakayama algebras, a bijection between indecomposable perfect differential modules and quiver representations, and a negative answer to the question of whether reflexivity of all simple modules forces self-injectivity. A reader should care because these results delimit when the classical Auslander definition of Gorenstein-projective modules agrees with later modern ones and provide concrete tools for computing them.

What carries the argument

The load-bearing tool is the ℧-operator, defined as the cokernel of a minimal left add(A)-approximation; it behaves as an inverse of the syzygy operator Ω and coincides with Tr Ω Tr. The ℧-quiver places each indecomposable non-projective module at a vertex and draws an arrow from X to ℧X whenever X is torsionless; the shape of the path through a vertex encodes whether the module is semi-Gorenstein-projective, ∞-torsionfree, reflexive, or Gorenstein-projective. The second essential object is the six-dimensional short local algebra Λ(q) = k⟨x,y,z⟩/⟨x², y², z², yz, xy+qyx, xz−zx, zy−zx⟩, whose 3-dimensional modules realize the missing (G1)+(G2)-but-not-(G3) example.

What would settle it

Recompute the modules over the six-dimensional algebra Λ(q) for a q of infinite multiplicative order and check whether some module satisfies (G1) and (G2) but fails (G3); if none exists, the independence theorem fails. Also check whether the email quoted in Remark 1.5 actually exists and says what is claimed; if it does not, the priority claim loses its direct evidence.

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Extended reading notes

Core claim

The central discovery attributed to the work is that the three total-reflexivity conditions are independent: for artin algebras there are modules satisfying (G1) and (G2) but not (G3), modules satisfying (G1) and (G3) but not (G2), and modules satisfying (G2) and (G3) but not (G1). The first class had been missing, and the surveyed work supplies it through the six-dimensional short local algebra Λ(q) and the module M(q) when q has infinite multiplicative order: M(q) is bi-semi-Gorenstein-projective but not torsionless, hence not Gorenstein-projective. Alongside this, the paper reports structural results: the Gorenstein core of a Nakayama algebra is the module category of a self-injective Nakayama algebra; over kQ[x]/(x²) the non-projective indecomposable Gorenstein-projective modules match the representations of Q; preprojective algebras of type A appear as factor categories of submodule categories; and short local algebras satisfy tight numerical restrictions on reflexive modules and a strong form of the Auslander–Reiten conjecture.

Load-bearing premise

The whole survey rests on the correctness of the published results it summarizes—especially the module classification over the six-dimensional algebra Λ(q)—and on the quoted 2018 email being authentic and accurate.

Editorial extensions

If this is right

  • If the independence theorem is correct, then no two of the three total-reflexivity conditions imply the third, so the class of bi-semi-Gorenstein-projective modules and the class of weakly Gorenstein algebras are genuinely non-redundant objects of study.
  • The ℧-quiver gives a direct visual criterion: an indecomposable module is Gorenstein-projective exactly when its vertex starts and ends an infinite ℧-path, so membership in the Gorenstein-projective class is read off from the component shape.
  • For connected Nakayama algebras without simple projectives, the Gorenstein core is an abelian Frobenius category equivalent to the module category of a self-injective Nakayama algebra, which makes the stable category of Gorenstein-projective modules accessible through a module category.
  • For Λ = kQ[x]/(x²), the homology functor sets up a bijection between indecomposable non-projective Gorenstein-projective Λ-modules and indecomposable kQ-modules; consequently Λ is CM-finite if and only if Q is Dynkin.
  • Over short local algebras, any non-projective reflexive module forces the Hilbert-type inequality 2 ≤ a ≤ e−1, and the Auslander–Reiten conjecture holds in the strong form that every non-projective semi-Gorenstein-projective module has nonzero Ext¹(M,M).

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The independence theorem suggests a template for building counterexamples in relative homological algebra: the same kind of short local algebra with a parameter of infinite order may produce modules that separate other pairs of Gorenstein-type conditions.
  • The ℧-quiver, because it encodes both syzygy and transpose duality, is likely to be a useful invariant beyond finite-dimensional algebras, for example in classifying Gorenstein-projective objects in monomorphism categories or Frobenius categories.
  • The bijection for quivers over dual numbers hints that other 1-Gorenstein algebras of the form A⊗kQ may admit similar homology-functor descriptions; testing k[x]/(x^n) for n>2 would be a natural next step.
  • The negative answer on simple reflexive modules means that reflexivity of all simples does not characterize self-injectivity; a natural open direction is whether the implication holds under finiteness conditions such as CM-finiteness or representation-finiteness.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

2 major / 5 minor

Summary. This article is a survey of Claus Michael Ringel's work on Gorenstein-projective modules, covering roughly the period 2012–2023. It summarizes his contributions to the independence problem for the total reflexivity conditions (G1), (G2), (G3); the technique of ℧-quivers; Gorenstein-projective modules over Nakayama algebras; representations of quivers over the algebra of dual numbers; the connection between submodule categories and preprojective algebras of type A; modules over short local algebras, including the Auslander–Reiten conjecture and Koszul modules; and his negative answer to Marczinzik's question on simple reflexive modules. The paper is primarily a review: it quotes theorems from published papers, gives examples, and credits Ringel with opening a new direction in relative homological algebra.

Significance. If taken as a survey, the article fills a useful gap by collecting scattered results into a single narrative, and it gives concrete, checkable pointers to the original papers. Its strength is that the core mathematical claims, including the independence theorem, are quoted from peer-reviewed sources rather than derived afresh. The survey is also valuable as a historical record of a coherent program of research. However, its central historical claim of priority for the independence theorem rests on an unverifiable private email whose wording is hedged, and the manuscript contains enough typographical and presentation errors that its reliability as a reference work is currently reduced. The paper would be acceptable after the priority claim is either softened or independently supported and after the presentation is cleaned up.

major comments (2)
  1. [Section 1.3 and Remark 1.5] The unqualified claim that Theorem 1.4 'first completely solves the independence problem' is not supported by the evidence offered. The quoted email from Christensen and Wu says the paper is 'probably the first' to demonstrate independence, and a private email cannot serve as a checkable citation. Since the 'first' claim is load-bearing for the paper's framing of Ringel's contribution, please either soften the claim to the checkable statement that Ringel and Zhang supplied the missing class of examples satisfying (G1) and (G2) but not (G3), or carry out and report a systematic literature search demonstrating that no earlier published module with that combination exists.
  2. [Section 1.5, Theorem 1.13] The attribution structure of Theorem 1.13 conflates sources. The theorem is labelled as coming from [RZ4, 1.2], but item (2) is separately credited to [HH, Theorem 4.2], and the surrounding discussion attributes results of Yoshino and Beligiannis to their papers without precise locations. For a survey whose value is partly historiographical, each equivalence in a composite theorem should carry its own citation so that the reader can verify exactly which statement comes from which paper.
minor comments (5)
  1. [Title page] The dedication contains the typo 'eightie th' and should read 'eightieth'.
  2. [Section 2, first paragraph] The sentence 'C. M. Ringel realized the importance of ℧-sequence and ℧-quiver is introduced in [RZ4]' is ungrammatical and should be rewritten, for example as 'C. M. Ringel realized the importance of ℧-sequences; the ℧-quiver was introduced in [RZ4].'
  3. [Section 5.1] The text 'F act 5.1' is a typo for 'Fact 5.1'; moreover, this fact is stated without proof or reference, so please either include a proof or cite a source.
  4. [Theorem 1.10(1)] The statement begins 'N is torsionless if and only if torsionless iff N is simple'; the duplicated phrase is confusing and should be corrected to 'N is torsionless if and only if N is simple or ...'.
  5. [Section 1.4, conversion formulas] The displayed conversion formulas after Theorem 1.10 mix left and right module notations in a way that is hard to follow, and some expressions, such as 'M'(1,−1,0)*≅Λ(x− qy)+Λ z', are not explained. Please standardize the notation and, ideally, include a pointer to the exact propositions in [RZ5] for each displayed formula.

Circularity Check

0 steps flagged · score 0.0 of 10

No circularity: this is a survey of independently published theorems; the priority claim is historical, not definitional.

full rationale

This is a survey article, not a derivation. Its mathematical assertions are quotations of published theorems in [RZ1]–[RZ8], [R1]–[R3], [M2], [JS], etc., with proofs in those papers; the survey itself does not fit parameters and then predict the same quantities, nor does it define any object in terms of its target claim. For example, Theorem 1.4 is quoted as “For artin algebras, the conditions (G1), (G2) and (G3) are independent” and is explicitly labeled “([RZ4, Theorem 1.7])”, pointing to an external published proof; the conditions (G1)–(G3) are defined earlier from Auslander’s work, not from the independence conclusion. The one load-bearing interpretive claim, that Theorem 1.4 “first completely solves” the independence problem, is supported by [RZ4] together with the private email quoted in Remark 1.5; this is a historical-priority assertion whose support may be thin or unverifiable, but it is not circular: the independence statement is not defined in terms of the priority claim, and the quoted email does not constrain the mathematical content of the theorem. Self-citation is present (P. Zhang co-authored many of the cited works, and the paper is dedicated to Ringel), but the cited results are published peer-reviewed theorems with independent proofs, so under the stated rules this self-citation is not load-bearing circularity. No step in the paper reduces to its own inputs by construction, and no fitted input is renamed as a prediction.

Assumptions & free parameters 0 free parameters · 2 assumptions · 0 invented entities

No new parameters, axioms, or entities are introduced; the paper is expository.

assumptions (2)
  • domain assumption The cited published theorems are correct
    The survey provides no proofs; its attributions inherit the correctness of [RZ1]-[RZ8] and [R1]-[R3].
  • ad hoc to paper The private email quoted in Remark 1.5 is genuine and accurate
    The priority claim for Theorem 1.4 depends on this unverifiable correspondence.

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Pith. "Pith review of Claus Michael Ringel's main contributions to Gorenstein-projective modules." pith.science (2026). https://pith.science/paper/MNNDTFHP

@misc{pith2026250512637,
  author       = {Pith},
  title        = {Pith review of: Claus Michael Ringel's main contributions to Gorenstein-projective modules},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/MNNDTFHP}},
  note         = {Machine review of arXiv:2505.12637}
}
abstract

In this article we try to recall Claus Michael Ringel's works on the Gorenstein-projective modules. This will involve but not limited to his fundamental contributions, such as in, the solution to the independence problem of totally reflexivity conditions; the technique of $\mho$-quivers; a fast algorithm to obtain the Gorenstein-projective modules over the Nakayama algebras; the one to one correspondence between the indecomposable non-projective perfect differential modules of a quiver and the indecomposable representations of this quiver; the description of the module category of the preprojective algebras of type $\mathbb A_n$ via submodule category; semi-Gorenstein-projective modules, reflexive modules, Koszul modules, as well as the $\Omega$-growth of modules, over short local algebras; and his negative answer to the question whether an algebra has to be self-injective in case all the simple modules are reflexive.

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Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. A survey on Auslander-Gorenstein algebras

    math.RT 2025-08 conditional novelty 3.0 of 10

    A survey of finite-dimensional Auslander-Gorenstein algebras, including classifications for monomial and incidence algebras and the identification of the Auslander-Reiten permutation with rowmotion, Ringel's homologic...

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Works this paper leans on

28 extracted references · 28 canonical work pages · cited by 1 Pith paper

  1. [1]

    Asadollahi, R

    [AHS] J. Asadollahi, R. Hafezi, S. Sadeghi, On the monomorph ism category of n-cluster tilting subcategories, Sci. China Math. 65(7)(2022), 1343-1362. [A] M. Auslander, Anneaux de Gorenstein et torsion en alg´ eb re commutative, S` eminaire d’alg´ ebre commuta- tive dirig´ e par P. Samuel (1966-1967), tome 1, notes by: M. M angeney, C. Peskine, L. Szpiro,...

  2. [13]

    [GKKP] N. Gao, J. K¨ ulshammer, S. Kvamme, C. Psaroudakis, A functorial approach to monomorphism categories II: Indecomposables, Proc. Lond. Math. Soc.(3)129(4)(202 4), e12640. [GLS] C. Geiss, B. Leclerc, J. Schr¨ oer, Quivers with relati ons for symmetrizable Cartan matrices I: Foundations, Invent. Math. 209(1)(2017), 61-158. [GP] I. M. Gelfand, V.A. Pon...

  3. [14]

    Herzog, S

    [HI] J. Herzog, S. Iyengar, Koszul modules, J. Pure Appl. Alg ebra 201(2005), 154 -

  4. [18]

    Kussin, H

    [KLM1] D. Kussin, H. Lenzing, H. Meltzer, Nilpotent operato rs and weighted projective lines, J. reine angew. Math. 685(6)(2010), 33-71. [KLM2] D. Kussin, H. Lenzing, H. Meltzer, Triangle singular ities, ADE-chains, and weighted projective lines, Adv. Math. 237(2013), 194-251. [Les] J. Lescot, Asymptotic properties of Betti numbers of m odules over certai...

  5. [36]

    [RZ5] C. M. Ringel, P. Zhang, Gorenstein-projective and sem i-Gorenstein-projective modules II, J. Pure Appl. Algebra 224 (2020), 106248. [RZ6] C. M. Ringel, P. Zhang, On modules M such that both M and M ∗ are semi-Gorenstein-projective, Algebr. Represent. Theory 24(2021), 1125 -

  6. [40]

    [CFH] L. W. Christensen, A. Frankild, H. Holm, On Gorenstein projective, injective and flat dimensions-a func- torial description with applications, J. Algebra 302(1)(2 006), 231-279. [CPST] L. W. Christensen, G. Piepmeyer, J. Striuli, R. Takah ashi, Finite Gorenstein representation type implies simple singularity, Adv. Math. 218(2008), 1012-1026. [CV] L. ...

  7. [73]

    [RZ2] C. M. Ringel, P. Zhang, Objective triangle functors, S ci. China Math. 58(2)(2015), 221 -

  8. [74]

    Auslander, I

    [AR2] M. Auslander, I. Reiten, Applications of contravaria ntly finite subcategories, Adv. Math. 86(1991), 111-152. [AR3] M. Auslander, I. Reiten, Cohen-Macaulay and Gorenste in artin algebras, In: Representation theory of finite groups and finite-dimensional algebras, Progress in M ath. vol. 95, 221-245, Birkh¨ auser, Basel,

Show all 28 references
  1. [114]

    [AIS] L. L. Avramov, S. B. Iyengar, L. M. S ¸ega, Free resoluti ons over short local rings, J. London Math. Soc. 78(2008), 459-476. [AM] L. L. Avramov, A. Martsinkovsky, Absolute, relative, a nd Tate cohomology of modules of finite Gorenstein dimension, Proc. London Math. Soc. ...

  2. [137]

    Huang, Z

    [HH] C. Huang, Z. Y. Huang, Torsionfree dimension of modules and self-injective dimension of rings, Osaka J. Math. 49(2012), 21-35. [HJS] M. T. Hughes, D. A. Jorgensen, L. M. S ¸ega, Acyclic comp lexes of finitely generated free modules over local ring, Math. Scand. 105 (2009),...

  3. [188]

    Holm, Gorenstein homological dimensions, J

    [Hol] H. Holm, Gorenstein homological dimensions, J. Pure A ppl. Algebra 189(1-3)(2004), 167-193. [Hos] M. Hoshino, Modules without self-extensions and Naka yama’s conjecture, Arch. Math. 43 (1982), 111 -

  4. [211]

    Beligiannis, On algebras of finite Cohen-Macaulay type, Adv

    [Bel3] A. Beligiannis, On algebras of finite Cohen-Macaulay type, Adv. Math. 226(2)(2011), 1973-2019. [BM] D. Bennis, N. Mahdou, Strongly Gorenstein projective, injective, and flat modules, J. Pure Appl. Algebra 210(2007), 437-445. [Bir] G. Birkhoff, Subgroups of abelian groups, ...

  5. [227]

    [R4] C. M. Ringel, The preprojective algebra of a quiver, In: Algebras and Modules II (Geiranger, 1996), CMS Conf. Proc. 24, 467 - 480, Amer. Math. Soc

  6. [232]

    [RZ3] C. M. Ringel, P. Zhang, Representations of quivers ove r the algebra of dual numbers, J. Algebra 475(2017), 327 -

  7. [261]

    [R2] C. M. Ringel, Simple reflexive modules over finite-dimen sional algebras, J. Algebra Appl. 20(9)(2021), 2150166. [R3] C. M. Ringel, The short local algebras of dimension 6 wit h non-projective reflexive modules, Comm. Math. Stat. 11(2)(2023), 195 -

  8. [317]

    Iyama, Y

    [IY] O. Iyama, Y. Yoshino, Mutation in triangulated categor ies and rigid Cohen-Macaulay modules, Invent. Math. 172(2008), 117-168. [JS] D. A. Jorgensen, L. M. S ¸ega, Independence of the total r eflexivity conditions for modules, Algebras and Representation Theory 9(2)(2006), ...

  9. [360]

    Special Issue in Memory of Prof. J. A. Green, Edited by B. Srinivasan, M. Collins and G. Lehrer. [RZ4] C. M. Ringel, P. Zhang, Gorenstein-projective and sem i-Gorenstein-projective modules, Algebra & Number Theory 14-1(2020), 1 -

  10. [589]

    Sather-W agstaff, T.Sharif, D

    [SWSW] S. Sather-W agstaff, T.Sharif, D. White, Stability of Gorenstein categories, J. Lond. Math. Soc. 77(2)(2008) 481-502. [S1] D. Simson, Representation types of the category of subp rojective representations of a finite poset over K[t]/(tm) and a solution of a Birkhoff type p...

  11. [1140]

    [RZ7] C. M. Ringel, P. Zhang, Koszul modules (and the Ω-growt h of modules) over short local algebras, J. Pure Appl. Algebra 225(2021), 1067772. [RZ8] C. M. Ringel, P. Zhang, Gorenstein-projective module s over short local algebras, J. Lond. Math. Soc. (2)106(2022), 528 -

  12. [1454]

    [DR] V. Dlab, C. M. Ringel, The module theoretical approach t o quasi-hereditary algebras, In: Representations of algebras and related topics (Kyoto, 1990), 200-224, LMS L NS 168, Cambridge Univ. Press,

  13. [1812]

    CLAUS MICHAEL RINGEL’S MAIN CONTRIBUTIONS TO GORENSTEIN-P ROJECTIVE MODULES 29 [LuoZ] X. H. Luo, P. Zhang, Monic representations and Gorens tein-projective modules, Pacific J. Math. 264(1)(2013), 163-194. [L] G. Lusztig, Quivers, perverse sheaves, and quantized en veloping alge...

  14. [1969]

    Auslander, I

    [AR1] M. Auslander, I. Reiten, On a generalization of the Nak ayama conjecture, Proc. Amer. Math. Soc. 52 (1975), 69 -

  15. [1982]

    Beligiannis, The homological theory of contravar iantly finite subcategories: auslander-buchweitz con- texts, gorenstein categories and (co-)stabilization, Com m

    [Bel1] A. Beligiannis, The homological theory of contravar iantly finite subcategories: auslander-buchweitz con- texts, gorenstein categories and (co-)stabilization, Com m. Algebra 28(10)(2000), 4547-4596. [Bel2] A. Beligiannis, Cohen-Macaulay modules, (co)torsi on pairs and vi...

  16. [1991]

    Auslander, I

    [AR4] M. Auslander, I. Reiten, Syzygy modules for Noetheria n rings, J. Algebra 183 (1996), 167-185. [ARS] M. Auslander, I. Reiten, S. O. Smalø, Representation T heory of Artin Algebras, Cambridge Studies in Adv. Math. 36., Cambridge Univ. Press,

  17. [1992]

    [EJ1] E. E. Enochs, O. M. G. Jenda, Gorenstein injective and p rojective modules, Math. Z. 220(4)(1995), 611-633. [EJ2] E. E. Enochs, O. M. G. Jenda, Relative homological alge bra, De Gruyter Exp. Math

  18. [1995]

    [AGP] L. L. Avramov, V. N. Gasharov, I. V. Peeva, Complete int ersection dimension, Inst. Hautes Etudes Sci. Publ. Math. 86 (1997), 67 -

  19. [1998]

    [R5] C. M. Ringel, The elementary 3-Kronecker modules, arXi v:1612.09141. [RS1] C. M. Ringel, M. Schmidmeier, Submodule categories of wild representation type, J. Pure Appl. Algebra 205(2)(2006), 412-422. [RS2] C. M. Ringel, M. Schmidmeier, The Auslander-Reiten tr anslation in...

  20. [2000]

    28 NAN GAO, XUE-SONG LU, PU ZHANG [CH] L. W. Christensen, H. Holm, Algebras that satisfy Ausla nder’s condition on vanishing of cohomology, Math. Z. 265(2010), 21 -

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