REVIEW 5 minor 1 cited by
If a Liouville domain is n-invertible, every Legendrian on its boundary has a Reeb chord of length at most the n-invertibility capacity.
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · grok-4.5
2026-07-12 13:51 UTC pith:32S3DOKJ
load-bearing objection Solid quantitative chord bound via a new capacity that settles Arnold for ST*T^n and submersion images of products of spheres.
Lengths of Reeb chords and Viterbo restriction
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Every Legendrian in the contact boundary of a Liouville domain Ω bounds a non-constant Reeb chord of period at most the n-invertibility capacity of Ω, whenever that capacity is finite. In particular the Arnold chord conjecture holds for the unit cotangent bundle of any manifold that is the base of a submersion from a product of spheres.
What carries the argument
n-invertibility capacity: the infimal action at which the unit of symplectic cohomology enters the smallest Δ-invariant ideal generated by the image of the top-degree PSS classes; non-vanishing of this capacity produces the contradiction after Viterbo restriction.
Load-bearing premise
The isomorphism that identifies string topology of the free loop space with symplectic cohomology of the cotangent bundle must preserve the products and BV operators that invert the top-degree classes.
What would settle it
An explicit compact Legendrian in the unit cotangent bundle of the n-torus that admits no Reeb chords for some contact form, or a computation showing that the unit never enters the ideal generated by the top PSS classes.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper introduces n-invertibility of a Liouville manifold W (Definition 1) and the associated capacity c_ni(Ω) (Definition 2), then proves that every Legendrian Λ ⊂ ∂Ω bounds a non-constant Reeb chord of period at most c_ni(Ω) whenever the capacity is finite (Theorem 3). The argument proceeds by constructing an exact embedding D_εT*Λ × D(a) when no short chords exist (Theorem 6), applying the Viterbo restriction map (Theorem 7) and a filtered Künneth isomorphism (Theorem 8) to force the unit to vanish in SH(T*Λ), and obtaining a contradiction with string topology. As applications, the authors show that T*(product of spheres) is n-invertible via explicit string-topology classes (Theorem 4), deduce the Arnold chord conjecture for ST*M whenever M admits a submersion from such a product (Theorem 10), and bound rationality constants of aspherical Lagrangians in unit disk cotangent bundles of tori (Theorem 5) via truncated Viterbo restriction (Theorem 11).
Significance. The work supplies a uniform, capacity-based upper bound on Reeb-chord lengths that recovers Zhou’s vanishing-SH results and extends them to aspherical bases such as T^n, where higher dilations and orientation tricks are unavailable. The geometric embedding of stabilized codisk bundles, the filtered Künneth map, and the truncated restriction for non-exact embeddings are carefully developed and of independent interest. The string-topology calculations that establish n-invertibility for products of spheres are topological and isolated from Floer theory, giving a clean, falsifiable criterion. Together these results settle the Arnold chord conjecture for a natural class of unit cotangent bundles and give the first rationality-constant bounds inside T*T^n.
minor comments (5)
- In Definition 1 and the subsequent persistence refinement, the notation for the ideal �_c and its colimit � is dense; a short clarifying sentence after Lemma 1.1 would help the reader track the filtration.
- Theorem 6 is stated for a Legendrian isotopy satisfying a strict inequality y*α > a dt; the subsequent reduction to the Reeb flow (Theorem 9) uses the non-strict version. A one-line remark on the limiting argument would remove any ambiguity.
- In §2.4.3 the homotopy between the classes P and D is continuous but not smooth; while the bordism-class model absorbs this, a parenthetical note that smoothing is possible would be reassuring.
- Appendix A.1.2 introduces the constants 7 and 3 without immediate motivation; a forward reference to the action-window estimates that follow would improve readability.
- A few typographical inconsistencies appear (e.g., “n-invertible domains always have dimension 2n” versus the later use of half-dimension convention; “�P^n” for RP^n). These are easily corrected.
Circularity Check
No significant circularity: capacity and geometric embedding are independent of the chord conclusion; self-citations to authors' prior Floer/string-topology framework transport topological calculations but do not force the result by definition.
specific steps
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self citation load bearing
[§1.2.2 / Theorem 4 and surrounding text]
"This proves that T*(S^{n1} imes⋯ imes S^{nk}) is n-invertible, due to the morphism of BV-algebras established in [Vit99, Vit96, AS06, Abo15, BC25]: H*(ΛM) o SH(T*M) sending [pt] to PSS(F) … Moreover, our argument also gives estimates on the n-invertibility capacity in terms of the lengths of the loops appearing in the classes A,B1,…,Bk, where the length functional is the one determined by the domain Ω⊂T*M considered in [BC25]."
The topological calculation of the invertibility relations is independent, but the passage that makes T*(product of spheres) n-invertible (hence c_ni finite, hence chords exist by Thm 3) relies on the BV-algebra morphism whose filtered version and conventions are developed in the authors' own prior paper [BC25]. The citation is load-bearing for the concrete examples (including ST*T^n) yet does not render the chord statement true by definition; the geometric embedding + restriction steps remain independent.
full rationale
The derivation chain is: no short Reeb chords imply exact embedding of D_εT*Λ imes D(a) (Thm 6, pure geometry via coisotropic embedding + Gotay-type neighborhood), Viterbo restriction (Thm 7, standard + appendix) and filtered Künneth (Thm 8, constructed via split Hamiltonians and almost-complex structures) kill PSS(H^n) hence the unit in SH(T*Λ), contradicting the known non-vanishing of the unit under the Viterbo isomorphism. The capacity c_ni is defined independently via the persistence module of the Δ-invariant ideal generated by PSS(H^n); it is not fitted to chord data. For the product-of-spheres examples the invertibility relations A*Δ(B*[pt])=[S^n] (and products) are computed by direct bordism/string-topology manipulations of maps (completing manifolds, generalized sections, open-book classes) entirely inside H_*(ΛM); the only transport is the classical BV-algebra morphism H_*(ΛM) o SH(T*M) cited from Viterbo–Abbondandolo–Schwarz–Abouzaid plus the authors' prior technical paper [BC25]. That citation is load-bearing for the examples but parameter-free, does not assume the chord conclusion, and is mixed with external references; it does not make the existence statement true by construction. Truncated restriction and asphericity lemmas for rationality constants are likewise external or geometric. No self-definitional loop, no fitted-input-as-prediction, no uniqueness smuggled from the authors, and no renaming of a known empirical pattern. Score 1 reflects only the minor self-citation that is not definitional for the central claim.
Axiom & Free-Parameter Ledger
axioms (4)
- standard math Existence and basic properties of the persistence module SH^c(Ω), the PSS map, the BV operator Δ and the pair-of-pants product (standard Floer theory over a field of characteristic 2).
- domain assumption Viterbo restriction (and its truncated version for non-exact embeddings) respects Δ, product and PSS, and maps free-homotopy summands correctly.
- domain assumption The BV-algebra morphism H*(ΛM) → SH(T*M) of Abbondandolo–Schwarz–Abouzaid–Viterbo that sends [pt] to the PSS image of a cotangent fibre.
- standard math No-escape lemma for Floer trajectories of the Viterbo Hamiltonian (AS10 Lemma 7.2).
invented entities (1)
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n-invertibility of a Liouville manifold (Definition 1) and the associated capacity c_ni(Ω) (Definition 2)
independent evidence
read the original abstract
Let $\Lambda$ be a Legendrian in the contact boundary of a Liouville domain $\Omega$. We explain how the non-existence of Reeb chords with endpoints on $\Lambda$ of length up to $a$ enables one to embed $D_{\epsilon}T^{*}\Lambda\times D(a)$ into $\Omega$ in an exact way. As in earlier work of Zhengyi Zhou, we use the Viterbo restriction map to deduce a contradiction in certain cases. In particular, we show that if $M$ admits a submersion from a product of spheres (e.g., the $n$-torus), then all compact Legendrians $\Lambda\subset ST^{*}M$ admit a Reeb chord for every choice of contact form $ST^{*}M$. The obstruction we use in this case is based on the idea of inverting the degree-$n$ classes in cohomology, and is similar to the notion of string point invertibility introduced by Egor Shelukhin.
Forward citations
Cited by 1 Pith paper
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The strong Arnol'd chord conjecture for the boundary of a uniformly convex domain in $\mathbb{R}^{4}$
Proves that any E3 Legendrian in the boundary of a Liouville domain bounds a chord of length at most liminf c_k(Ω)/k and applies this to establish the strong Arnol'd chord conjecture for uniformly convex domains in R^4.
Reference graph
Works this paper leans on
-
[1]
H. Alizadeh, M. S. Atallah, and D. Cant, Lagrangian intersections and the spectral norm in convex-at-infinity symplectic manifolds, Math. Z. 310 (2025), no. 2, 1--48, doi:10.1007/s00209-025-03710-0 https://doi.org/10.1007/s00209-025-03710-0
-
[2]
B. Albach, J-F. Barraud, M. Bialy, J. Bimmermann, A. Chávez Cáliz, M. Damian, L. Deschamps, U. Hryniewicz, V. Humilière, B. Khesin, L. Maier, A. Moreno, A. Oancea, O. Paris-Romaskevich, A. Sorrentino, and S. Tabachnikov, Open problems in billiards and quantitative symplectic geometry, arXiv:2602.12896, 2026, doi:10.48550/arXiv.2602.12896 https://doi.org/1...
-
[4]
P. Albers, K. Cieliebak, and U. Frauenfelder, Symplectic T ate homology , Proc. London Math. Soc. 3 (2016), no. 112, 169--205, doi:10.1112/plms/pdv065 https://doi.org/10.1112/plms/pdv065
-
[5]
M. S. Atallah, J.-P. Chassé, R. Leclercq, and E. Shelukhin, Weinstein exactness of nearby L agrangians: towards the L agrangian C^ 0 flux conjecture , arXiv:2410.04158, 2024, doi:10.48550/arXiv.2410.04158 https://doi.org/10.48550/arXiv.2410.04158
-
[6]
P. Albers, U. Frauenfelder, and A. Oancea, Local systems on the free loop space and finiteness of the Hofer-Zehnder capacity , Mathematische Annalen 367 (2017), no. 3, 1403--1428, doi:10.1007/s00208-016-1401-6 https://doi.org/10.1007/s00208-016-1401-6
-
[7]
A. Abbondandolo, A. Portaluri, and M. Schwarz, The homology of path spaces and F loer homology with conormal boundary conditions , J. Fixed Point Theory Appl. 4 (2008), 263--293, doi:10.1007/S11784-008-0097-Y https://doi.org/10.1007/S11784-008-0097-Y
-
[8]
V. I. Arnol'd, First steps in symplectic topology, Russian Mathematical Surveys 41 (1986), no. 6, 1, doi:10.1070/RM1986v041n06ABEH004221 https://doi.org/10.1070/RM1986v041n06ABEH004221
-
[9]
A. Abbondandolo and M. Schwarz, On the F loer homology of cotangent bundles , Comm. Pure Appl. Math. 59 (2006), 254--316, doi:10.1002/cpa.20090 https://doi.org/10.1002/cpa.20090
-
[10]
M. Abouzaid and P. Seidel, An open string analogue of V iterbo functoriality , Geom. Topol. 14 (2010), 627--718, doi:10.2140/gt.2010.14.627 https://doi.org/10.2140/gt.2010.14.627
-
[11]
F. Bro\'ci\'c and D. Cant, Bordism classes of loops and F loer's equation in cotangent bundles , J. Fixed Point Theory Appl. 26 (2024), 1--29, doi:10.1007/s11784-024-01114-x https://doi.org/10.1007/s11784-024-01114-x
-
[12]
, Parametric G romov width for L iouville domains , arXiv:2504.15207, 04 2025, doi:10.48550/arXiv.2504.15207 https://doi.org/10.48550/arXiv.2504.15207
work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2504.15207 2025
-
[13]
F. Bro \'c i \'c , D. Cant, and E. Shelukhin, The chord conjecture for conormal bundles, Math. Ann. (2025), 63, doi:10.1007/s00208-025-03171-0 https://doi.org/10.1007/s00208-025-03171-0
-
[14]
J. Bimmermann, H ofer– Z ehnder capacity of magnetic disc tangent bundles over constant curvature surfaces , Arch. Math. 123 (2024), 103--111, doi:10.1007/s00013-024-02003-y https://doi.org/10.1007/s00013-024-02003-y
-
[15]
Floer, Symplectic fixed points and holomorphic spheres, Comm
A. Floer, Symplectic fixed points and holomorphic spheres, Comm. Math. Phys. 120 (1989), no. 4, 575--611
1989
-
[16]
U. Frauenfelder and A. Pajitnov, Finiteness of _ 1 -sensitive H ofer- Z ehnder capacity and equivariant loop space homology , J. Fixed Point Theory Appl. 19 (2017), 3--15, doi:10.1007/s11784-016-0345-5 https://doi.org/10.1007/s11784-016-0345-5
-
[17]
Frauenfelder and F
U. Frauenfelder and F. Schlenk, Hamiltonian dynamics on convex symplectic manifolds, Isr. J. Math. 159 (2007), 1--56
2007
-
[18]
Goodwillie, Cyclic homology, derivations, and the free loopspace, Topology 24 (1985), no
T. Goodwillie, Cyclic homology, derivations, and the free loopspace, Topology 24 (1985), no. 2, 187--215, doi:10.1016/0040-9383(85)90055-2 https://doi.org/10.1016/0040-9383(85)90055-2
-
[19]
M. J. Gotay, On coisotropic imbeddings of presymplectic manifolds, Proc. Amer. Math. Soc. 84 (1982), no. 1, 111--114
1982
-
[20]
Guo and Z
K. Guo and Z. Zhou, The Arnol'd chord conjecture for ST^ * T^ 3 , submitted to arXiv, 2026
2026
-
[21]
Hofer and D
H. Hofer and D. Salamon, Floer homology and N ovikov rings , The Floer memorial volume, Progr. Math., vol. 133, Birkh \"a user, 1995, pp. 483--524
1995
-
[22]
M. Hutchings and C. H. Taubes, Proof of the Arnold chord conjecture in three dimensions. I , Math. Res. Lett. 18 (2011), no. 2, 295--313, doi:10.4310/MRL.2011.V18.N2.A8 https://doi.org/10.4310/MRL.2011.V18.N2.A8
-
[23]
, Proof of the Arnold chord conjecture in three dimensions. II , Geom. Topol. 17 (2013), 2601--2688, doi:10.2140/gt.2013.17.2601 https://doi.org/10.2140/gt.2013.17.2601
-
[24]
Irie, H ofer- Z ehnder capacity of unit disk cotangent bundles and the loop product , J
K. Irie, H ofer- Z ehnder capacity of unit disk cotangent bundles and the loop product , J. Eur. Math. Soc. 16 (2014), 2477--2497, doi:10.4171/JEMS/491 https://doi.org/10.4171/JEMS/491
-
[25]
Kang, On the strong Arnold chord conjecture for convex contact forms , J
J. Kang, On the strong Arnold chord conjecture for convex contact forms , J. Topol. 19 (2026), no. 1, 1--24, doi:10.1112/topo.70062 https://doi.org/10.1112/topo.70062
-
[26]
J. Kang and J. Zhang, Strong A rnold chord conjecture via normalized capacities , arXiv:2404.05150, 2024, doi:10.48550/arXiv.2404.05150 https://doi.org/10.48550/arXiv.2404.05150
-
[28]
Y. Li, Aspherical L agrangian submanifolds, A udin's conjecture and cyclic dilations , arXiv:2308.05086, 2023, pp. 1--81
Pith/arXiv arXiv 2023
-
[29]
15 (2024), 123--227, doi:10.4171/QT/199 https://doi.org/10.4171/QT/199
, Exact C alabi- Y au categories and odd-dimensional L agrangian spheres , Quantum Topol. 15 (2024), 123--227, doi:10.4171/QT/199 https://doi.org/10.4171/QT/199
-
[30]
Mark McLean, Lefschetz fibrations and symplectic homology, Geom. T opol. 13 (2009), no. 4, 1877--1944
2009
-
[31]
Menichi, String topology for spheres, Comment
L. Menichi, String topology for spheres, Comment. Math. Helv. 84 (2009), 135--157, doi:https://doi.org/10.4171/CMH/155 https://doi.org/https://doi.org/10.4171/CMH/155
-
[32]
Mohnke, Holomorphic disks and the chord conjecture, Ann
K. Mohnke, Holomorphic disks and the chord conjecture, Ann. Math. 154 (2001), 219--222, doi:10.2307/3062116 https://doi.org/10.2307/3062116
-
[33]
McDuff and D
D. McDuff and D. Salamon, Introduction to symplectic topology, 3rd ed., Oxford Graduate Texts in Mathematics, no. 27, Oxford University Press, 2012
2012
-
[34]
, J -holomorphic curves and symplectic topology , 2nd ed., American Mathematical Society, Colloquium Publications, 2012
2012
-
[35]
Oancea, Fibered symplectic cohomology and the L eray- S erre spectral sequence , J
A. Oancea, Fibered symplectic cohomology and the L eray- S erre spectral sequence , J. Symp. Geom. 6 (2008), no. 3, 267--351
2008
-
[36]
67--109, doi:10.4171/153 https://doi.org/10.4171/153
A Oancea, Morse theory, closed geodesics, and the homology of free loop spaces, Free Loop Spaces in Geometry and Topology, European Mathematical Society, 2015, pp. 67--109, doi:10.4171/153 https://doi.org/10.4171/153
doi:10.4171/153 2015
-
[37]
Opshtein, Legendrian barriers in prequantization bundles, arXiv:2512.18808v1, 2025
E. Opshtein, Legendrian barriers in prequantization bundles, arXiv:2512.18808v1, 2025
Pith/arXiv arXiv 2025
-
[38]
Polterovich and E
L. Polterovich and E. Shelukhin, Autonomous H amiltonian flows, H ofer's geometry, and persistence modules , Sel. Math. New. Ser. 22 (2016), 227--296
2016
-
[39]
Piunikhin, D
S. Piunikhin, D. Salamon, and M. Schwarz, Symplectic F loer- D onaldson theory and quantum cohomology , Contact and symplectic geometry ( C ambridge, 1994), Publ. Newton Inst., vol. 8, Cambridge Univ. Press, Cambridge, 1996, pp. 171--200
1994
-
[40]
Ritter, Topological quantum field theory structure on symplectic cohomology, J
A. Ritter, Topological quantum field theory structure on symplectic cohomology, J. Topol. 6 (2013), 391--489, doi:10.1112/jtopol/jts038 https://doi.org/10.1112/jtopol/jts038
-
[41]
Schwarz, On the action spectrum for closed symplectically aspherical manifolds, Pacific J
M. Schwarz, On the action spectrum for closed symplectically aspherical manifolds, Pacific J. Math. 193 (2000), 419--461
2000
-
[42]
Seidel, A biased view of symplectic cohomology, Current developments in mathematics, 2006, Int
P. Seidel, A biased view of symplectic cohomology, Current developments in mathematics, 2006, Int. Press, Somerville, MA, 2008, pp. 211--253, doi:10.4310/CDM.2006.V2006.N1.A4 https://doi.org/10.4310/CDM.2006.V2006.N1.A4
-
[43]
, A remark on the symplectic cohomology of cotangent bundles, after K ragh , https://math.mit.edu/ seidel/texts/cp2.pdf, 2010, Date accessed: May 8th 2026
2010
-
[44]
, Disjoinable L agrangian spheres and dilations , Invent. Math. 197 (2014), 299--359, doi:10.1007/s00222-013-0484-x https://doi.org/10.1007/s00222-013-0484-x
-
[45]
Shelukhin, Symplectic cohomology and a conjecture of V iterbo , Geom
E. Shelukhin, Symplectic cohomology and a conjecture of V iterbo , Geom. Funct. Anal. 32 (2022), 1514--1543, doi:10.1007/s00039-022-00619-2 https://doi.org/10.1007/s00039-022-00619-2
-
[46]
P. Seidel and J. P. Solomon, Symplectic cohomology and q -intersection numbers , Geom. Funct. Anal. 22 (2012), 443--477, doi:10.1007/s00039-012-0159-6 https://doi.org/10.1007/s00039-012-0159-6
-
[47]
C. Viterbo, Functors and computations in F loer homology with applications, part II , arXiv:1805.01316v1, 1996, doi:10.48550/arXiv.1805.01316 https://doi.org/10.48550/arXiv.1805.01316
-
[48]
C Viterbo, Functors and computations in F loer homology with applications, i , Geom. Funct. Anal. 9 (1999), no. 5, 985--1033, doi:1016-443X/99/050985-49 https://doi.org/1016-443X/99/050985-49
1999
-
[49]
Zhao, Periodic symplectic cohomologies and obstructions to exact L agrangian immersions , Doctoral Thesis at Columbia University, 2016
J. Zhao, Periodic symplectic cohomologies and obstructions to exact L agrangian immersions , Doctoral Thesis at Columbia University, 2016
2016
-
[50]
Zhou, Symplectic fillllings of asymptotically dynamically convex manifolds I , J
Z. Zhou, Symplectic fillllings of asymptotically dynamically convex manifolds I , J. Topol. 14 (2021), 112--182, doi:10.1112/topo.12177 https://doi.org/10.1112/topo.12177
-
[51]
, On the minimal symplectic area of L agrangians , J. Symplectic Geom. 20 (2022), no. 6, 1385--1413, doi:10.4310/jsg.2022.v20.n6.a5 https://doi.org/10.4310/jsg.2022.v20.n6.a5
-
[52]
, Symplectic fillings of asymptotically dynamically convex manifolds II -- k -dilations , Adv. Math. 406 (2022), 1--62, doi:10.1016/j.aim.2022.108522 https://doi.org/10.1016/j.aim.2022.108522
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