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arxiv: 2603.29926 · v2 · submitted 2026-03-31 · ✦ hep-th

Recognition: 2 theorem links

· Lean Theorem

Recursive-algebraic solution of the closed string tachyon vacuum equation

Authors on Pith no claims yet

Pith reviewed 2026-05-13 23:17 UTC · model grok-4.3

classification ✦ hep-th
keywords tachyon vacuumclosed string field theoryseam-graded expansionhyperbolic recursionalgebraic solutionmatrix inversionzero-momentum sector
0
0 comments X

The pith

In the zero-momentum Lorentz-scalar sector the closed string tachyon vacuum equation reduces to recursive matrix inversions via a seam-graded expansion.

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

The paper develops a recursive algebraic framework for the closed string tachyon vacuum equation drawn from hyperbolic recursion relations. It restricts attention to zero-momentum Lorentz-scalar states, a sector that Lorentz symmetry keeps closed under the equations of motion. A seam-graded expansion is introduced in which the unknown at each grade appears only through its value at the systolic length. Consequently every order reduces to a finite matrix inversion with no Fredholm integral equations to solve. The resulting series is formal; convergence questions are left open.

Core claim

We develop a recursive algebraic framework for solving the closed string tachyon vacuum equation, derived from the hyperbolic recursion relations of Fırat and Valdes-Meller. We restrict to the sector of zero-momentum Lorentz-scalar states. Lorentz symmetry ensures that this sector is closed under the equations of motion. In this sector, we introduce a seam-graded expansion and show that the equation is entirely algebraic at every order: the unknown at each grade enters only through point evaluations at the systolic length, so each grade reduces to a matrix inversion with no Fredholm equations. The expansion is formal; convergence in the multi-level system is the subject of ongoing work.

What carries the argument

The seam-graded expansion, which organizes fields by seam length so that the tachyon vacuum equation closes algebraically through point evaluations at the systolic length.

If this is right

  • Each successive order is obtained by inverting a finite matrix whose entries come from known lower-order data.
  • The solution is built entirely from linear algebra without ever solving an integral equation.
  • The zero-momentum Lorentz-scalar sector remains invariant under the full dynamics, justifying the restriction.
  • The method applies order by order to the hyperbolic recursion relations that define the closed-string equations.

Where Pith is reading between the lines

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

  • If the formal series converges, the resulting explicit solution could be used to extract numerical values for the tachyon condensate and related observables.
  • The algebraic closure at each grade may extend to other closed-string sectors or to open-string analogs if a similar grading can be identified.
  • Truncation of the recursion at finite order would give a systematic approximation scheme whose error can be bounded once convergence is established.

Load-bearing premise

The formal seam-graded series converges to an actual solution of the original equation in the multi-level system.

What would settle it

Explicit computation of the first several orders followed by direct substitution back into the tachyon vacuum equation would confirm consistency at those orders; a mismatch already at low order would falsify the reduction.

read the original abstract

We develop a recursive algebraic framework for solving the closed string tachyon vacuum equation, derived from the hyperbolic recursion relations of F{\i}rat and Valdes-Meller. We restrict to the sector of zero-momentum Lorentz-scalar states. Lorentz symmetry ensures that this sector is closed under the equations of motion. In this sector, we introduce a seam-graded expansion and show that the equation is entirely algebraic at every order: the unknown at each grade enters only through point evaluations at the systolic length, so each grade reduces to a matrix inversion with no Fredholm equations. The expansion is formal; convergence in the multi-level system is the subject of ongoing work. This work was conducted with a publicly available version of Claude Code (Anthropic, Claude Opus 4.6). The complete research repository, including all computations, adversarial review logs, and the full human-AI collaboration history, is publicly available at https://github.com/mk2427/csft-tachyon-vacuum.

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

2 major / 1 minor

Summary. The manuscript develops a recursive-algebraic framework for solving the closed string tachyon vacuum equation, derived from the hyperbolic recursion relations of Fırat and Valdes-Meller. It restricts attention to the zero-momentum Lorentz-scalar sector, which is closed under the equations of motion by Lorentz symmetry, and introduces a seam-graded expansion in which the equation at each order reduces to an algebraic system: the unknown enters solely through point evaluations at the systolic length, yielding a matrix inversion with no residual Fredholm integral operators. The expansion is explicitly formal; convergence of the resulting multi-level series is deferred to ongoing work.

Significance. If the formal series converges in a suitable topology on the string-field Hilbert space, the method would supply an efficient, purely algebraic recursive procedure for constructing the tachyon vacuum in the closed-string sector, bypassing integral equations at each grade. The public repository containing all computations, adversarial review logs, and the full collaboration history is a clear strength for reproducibility. The reduction to matrix inversion, when verified, would constitute a technical advance over existing numerical or perturbative approaches in closed string field theory.

major comments (2)
  1. [Abstract / seam-graded expansion section] Abstract and the section introducing the seam-graded expansion: the claim that the equation becomes entirely algebraic at every order, with the unknown entering only via point evaluations at the systolic length, is asserted without an explicit low-order derivation or sample computation. An explicit calculation of the first grade (or first two grades) is required to confirm that subtraction of lower-grade contributions leaves no residual integral operators from the underlying hyperbolic recursion relations.
  2. [Formal series / convergence discussion] The section on the formal series and convergence: while the manuscript correctly states that convergence is the subject of ongoing work, the central claim of a 'solution' to the tachyon vacuum equation remains conditional on a separate proof that the series converges in a normed space containing the string-field Hilbert space. Without even a candidate topology or a statement that the series is at least asymptotic, the algebraic procedure does not yet deliver an element of the physical state space.
minor comments (1)
  1. [Abstract] The abstract mentions the use of Claude Code and points to the GitHub repository; moving this disclosure to an acknowledgments section would keep the abstract focused on the technical result.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the careful reading and constructive comments. We respond to each major comment below.

read point-by-point responses
  1. Referee: [Abstract / seam-graded expansion section] Abstract and the section introducing the seam-graded expansion: the claim that the equation becomes entirely algebraic at every order, with the unknown entering only via point evaluations at the systolic length, is asserted without an explicit low-order derivation or sample computation. An explicit calculation of the first grade (or first two grades) is required to confirm that subtraction of lower-grade contributions leaves no residual integral operators from the underlying hyperbolic recursion relations.

    Authors: We agree that an explicit low-order derivation would strengthen the presentation. In the revised manuscript we will add a detailed calculation of the first grade in the seam-graded expansion section. This will show step by step how subtraction of lower-grade contributions removes all residual integral operators from the hyperbolic recursion relations, leaving only point evaluations at the systolic length that reduce to a matrix inversion. revision: yes

  2. Referee: [Formal series / convergence discussion] The section on the formal series and convergence: while the manuscript correctly states that convergence is the subject of ongoing work, the central claim of a 'solution' to the tachyon vacuum equation remains conditional on a separate proof that the series converges in a normed space containing the string-field Hilbert space. Without even a candidate topology or a statement that the series is at least asymptotic, the algebraic procedure does not yet deliver an element of the physical state space.

    Authors: The manuscript already describes the result as a formal series whose convergence is deferred to ongoing work. In the revision we will add an explicit statement clarifying that the algebraic procedure produces a formal series solution in the zero-momentum scalar sector and that convergence in a suitable topology on the string-field Hilbert space (or at minimum an asymptotic property) is required before it corresponds to a physical state. This will be added as a brief clarifying paragraph without changing the main claims. revision: yes

Circularity Check

0 steps flagged

No circularity: algebraic reduction follows from explicit expansion choice and external recursion relations

full rationale

The derivation begins from the hyperbolic recursion relations of Fırat and Valdes-Meller (external prior work with no author overlap) and introduces a new seam-graded expansion restricted to the zero-momentum Lorentz-scalar sector, which is closed by Lorentz symmetry. The paper states that this expansion makes the equation algebraic at each order because the unknown enters solely via point evaluations at the systolic length, reducing each grade to matrix inversion. This is presented as a direct consequence of the grading and sector choice rather than a tautological redefinition or fitted input renamed as prediction. No load-bearing self-citation, uniqueness theorem imported from the same authors, or ansatz smuggled via citation appears; convergence is explicitly left open as ongoing work, but the formal recursive procedure itself does not reduce to its inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The framework rests on the domain assumption that the zero-momentum Lorentz-scalar sector is closed under the equations of motion and on the prior hyperbolic recursion relations of Fırat and Valdes-Meller; no free parameters or invented entities are introduced in the abstract.

axioms (1)
  • domain assumption Lorentz symmetry ensures that the zero-momentum Lorentz-scalar sector is closed under the equations of motion.
    Stated directly in the abstract as the justification for restricting to this sector.

pith-pipeline@v0.9.0 · 5463 in / 1294 out tokens · 35796 ms · 2026-05-13T23:17:47.646812+00:00 · methodology

discussion (0)

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Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

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matches
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supports
The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends
The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
uses
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contradicts
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unclear
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Reference graph

Works this paper leans on

72 extracted references · 72 canonical work pages · 14 internal anchors

  1. [1]

    Analytic solution for tachyon condensation in open string field theory

    M. Schnabl,Analytic solution for tachyon condensation in open string field theory, Adv. Theor. Math. Phys.10(2006) 433–501, [hep-th/0511286]

  2. [2]

    Comments on Schnabl's analytic solution for tachyon condensation in Witten's open string field theory

    Y. Okawa,Comments on Schnabl’s analytic solution for tachyon condensation in Witten’s open string field theory,JHEP04(2006) 055, [hep-th/0603159]

  3. [3]

    A Simple Analytic Solution for Tachyon Condensation

    T. Erler and M. Schnabl,A Simple Analytic Solution for Tachyon Condensation, JHEP10(2009) 066, [0906.0979]

  4. [4]

    Erler and C

    T. Erler and C. Maccaferri,String field theory solution for any open string background, JHEP10(2014) 029, [1406.3021]

  5. [5]

    Solutions from boundary condition changing operators in open string field theory

    M. Kiermaier, Y. Okawa and P. Soler,Solutions from boundary condition changing operators in open string field theory,JHEP03(2011) 122, [1009.6185]

  6. [6]

    Murata and M

    M. Murata and M. Schnabl,Multibrane solutions in open string field theory,JHEP07 (2012) 063, [1112.0591]

  7. [7]

    On the validity of the solution of string field theory

    E. Fuchs and M. Kroyter,On the validity of the solution of string field theory,JHEP 05(2006) 006, [hep-th/0603195]

  8. [8]

    Marginal deformations in string field theory

    E. Fuchs, M. Kroyter and R. Potting,Marginal deformations in string field theory, JHEP09(2007) 101, [0704.2222]

  9. [9]

    Gaiotto and L

    D. Gaiotto and L. Rastelli,Experimental string field theory,JHEP08(2003) 048, [hep-th/0211012]

  10. [10]

    Level truncation and the tachyon in open bosonic string field theory

    N. Moeller and W. Taylor,Level truncation and the tachyon in open bosonic string field theory,Nucl. Phys. B583(2000) 105–144, [hep-th/0002237]

  11. [11]

    Erler,Four Lectures on Analytic Solutions in Open String Field Theory,Phys

    T. Erler,Four Lectures on Analytic Solutions in Open String Field Theory,Phys. Rept.980(2022) 1–95, [1912.00521]

  12. [12]

    A Closed String Tachyon Vacuum ?

    H. Yang and B. Zwiebach,A Closed string tachyon vacuum?,JHEP09(2005) 054, [hep-th/0506077]

  13. [13]

    Dualities of Type 0 Strings

    O. Bergman and M. R. Gaberdiel,Dualities of Type 0 Strings,JHEP07(1999) 022, [hep-th/9906055]

  14. [14]

    Erler,The closed string field theory action vanishes,JHEP10(2022) 055, [2204.12863]

    T. Erler,The closed string field theory action vanishes,JHEP10(2022) 055, [2204.12863]

  15. [15]

    Erler and A

    T. Erler and A. H. Fırat,Wilsonian effective potentials and closed string field theory, JHEP02(2024) 018, [2311.17322]

  16. [16]

    Sen and B

    A. Sen and B. Zwiebach,String Field Theory — A Review,2405.19421

  17. [17]

    Erbin,String Field Theory: A Modern Introduction,

    H. Erbin,String Field Theory: A Modern Introduction,

  18. [18]

    Maccaferri,String Field Theory,2308.00875

    C. Maccaferri,String Field Theory,2308.00875

  19. [20]

    Sen,Gauge Invariant 1PI Effective Action for Superstring Field Theory,JHEP06 (2015) 022, [1411.7478]

    A. Sen,Gauge Invariant 1PI Effective Action for Superstring Field Theory,JHEP06 (2015) 022, [1411.7478]

  20. [21]

    Sen,Gauge Invariant 1PI Effective Superstring Field Theory: Inclusion of the Ramond Sector,JHEP08(2015) 025, [1501.00988]

    A. Sen,Gauge Invariant 1PI Effective Superstring Field Theory: Inclusion of the Ramond Sector,JHEP08(2015) 025, [1501.00988]

  21. [22]

    Sen,BV Master Action for Heterotic and Type II String Field Theories,JHEP02 (2016) 087, [1508.05387]

    A. Sen,BV Master Action for Heterotic and Type II String Field Theories,JHEP02 (2016) 087, [1508.05387]

  22. [23]

    Faroogh Moosavian and R

    S. Faroogh Moosavian and R. Pius,Hyperbolic geometry and closed bosonic string field theory. I. The string vertices via hyperbolic Riemann surfaces,JHEP08(2019) 157, [1706.07366]

  23. [24]

    Sen,D-instantons, string field theory and two dimensional string theory,JHEP11 (2021) 061, [2012.11624]

    A. Sen,D-instantons, string field theory and two dimensional string theory,JHEP11 (2021) 061, [2012.11624]

  24. [25]

    Sen,D-instanton Perturbation Theory,JHEP08(2020) 075, [2002.04043]

    A. Sen,D-instanton Perturbation Theory,JHEP08(2020) 075, [2002.04043]

  25. [26]

    Sen,Normalization of D-instanton amplitudes,JHEP11(2021) 077, [2101.08566]

    A. Sen,Normalization of D-instanton amplitudes,JHEP11(2021) 077, [2101.08566]

  26. [27]

    Sen,Normalization of type IIB D-instanton amplitudes,JHEP12(2021) 146, [2104.11109]

    A. Sen,Normalization of type IIB D-instanton amplitudes,JHEP12(2021) 146, [2104.11109]

  27. [28]

    Sen,Muti-instanton amplitudes in type IIB string theory,JHEP12(2021) 065, [2104.15110]

    A. Sen,Muti-instanton amplitudes in type IIB string theory,JHEP12(2021) 065, [2104.15110]

  28. [30]

    D. S. Eniceicu, R. Mahajan, P. Maity, C. Murdia and A. Sen,The ZZ annulus one-point function in non-critical string theory: A string field theory analysis,JHEP 12(2022) 151, [2210.11473]

  29. [31]

    D. S. Eniceicu, R. Mahajan, C. Murdia and A. Sen,Multi-instantons in minimal string theory and in matrix integrals,JHEP10(2022) 065, [2206.13531]

  30. [32]

    Chakravarty and A

    J. Chakravarty and A. Sen,Normalization of D instanton amplitudes in two dimensional type 0B string theory,JHEP02(2023) 170, [2207.07138]

  31. [33]

    Alexandrov, A

    S. Alexandrov, A. Sen and B. Stefa´ nski,D-instantons in Type IIA string theory on Calabi-Yau threefolds,JHEP11(2021) 018, [2108.04265]

  32. [34]

    Alexandrov, A

    S. Alexandrov, A. Sen and B. Stefa´ nski,Euclidean D-branes in type IIB string theory on Calabi-Yau threefolds,JHEP12(2021) 044, [2110.06949]

  33. [35]

    Alexandrov, A

    S. Alexandrov, A. H. Fırat, M. Kim, A. Sen and B. Stefa´ nski,D-instanton induced superpotential,JHEP07(2022) 090, [2204.02981]

  34. [36]

    N. B. Agmon, B. Balthazar, M. Cho, V. A. Rodriguez and X. Yin,D-instanton Effects in Type IIB String Theory,2205.00609

  35. [37]

    Sen,D-instanton induced effective action and its gauge invariance,JHEP06(2025) 225, [2407.06278]

    A. Sen,D-instanton induced effective action and its gauge invariance,JHEP06(2025) 225, [2407.06278]

  36. [38]

    Scheinpflug, Y

    J. Scheinpflug, Y. Wang and X. Yin,D-instanton Effects on a D3-brane,2602.21281. 45

  37. [39]

    Sen and B

    A. Sen and B. Stef´ anski, jr.,Scattering of D0-branes and Strings,JHEP01(2026) 033, [2509.02716]

  38. [40]

    M. Cho, S. Collier and X. Yin,Strings in Ramond-Ramond Backgrounds from the Neveu-Schwarz-Ramond Formalism,JHEP12(2020) 123, [1811.00032]

  39. [41]

    Cho and M

    M. Cho and M. Kim,A worldsheet description of flux compactifications,JHEP05 (2024) 247, [2311.04959]

  40. [42]

    Kim,String perturbation theory of Klebanov-Strassler throat,JHEP05(2025) 234, [2409.19048]

    M. Kim,String perturbation theory of Klebanov-Strassler throat,JHEP05(2025) 234, [2409.19048]

  41. [43]

    M. Cho, J. Gomide, J. Scheinpflug and X. Yin,On theAdS 5 ×S 5 Solution of Superstring Field Theory,2507.12921

  42. [44]

    Frenkel and M

    A. Frenkel and M. Kim,Non-linear sigma model in string field theory,2509.20527

  43. [45]

    Stettinger,A boundary term for open string field theory,JHEP05(2025) 226, [2411.15123]

    G. Stettinger,A boundary term for open string field theory,JHEP05(2025) 226, [2411.15123]

  44. [46]

    A. H. Fırat and R. A. Mamade,Boundary terms in string field theory,JHEP02 (2025) 058, [2411.16673]

  45. [47]

    Maccaferri, R

    C. Maccaferri, R. Poletti, A. Ruffino and J. Voˇ smera,Boundary modes in string field theory,JHEP06(2025) 108, [2502.19373]

  46. [48]

    Maccaferri, A

    C. Maccaferri, A. Ruffino and J. Voˇ smera,Gauge-invariant action for free string field theory with boundary,JHEP01(2026) 161, [2506.05969]

  47. [49]

    M. Cho, B. Mazel and X. Yin,Rolling tachyon and the phase space of open string field theory,JHEP04(2025) 129, [2310.17895]

  48. [50]

    Bernardes, T

    V. Bernardes, T. Erler and A. H. Fırat,Symplectic structure in open string field theory. Part II. Sliding lump,JHEP02(2026) 064, [2511.15781]

  49. [51]

    Bernardes, T

    V. Bernardes, T. Erler and A. H. Fırat,Symplectic structure in open string field theory. Part I. Rolling tachyons,JHEP02(2026) 063, [2511.03777]

  50. [52]

    Bernardes, T

    V. Bernardes, T. Erler and A. H. Fırat,Covariant phase space and L ∞ algebras,JHEP 09(2025) 057, [2506.20706]

  51. [53]

    Choi,Higher Connection in Open String Field Theory,2602.13627

    Y. Choi,Higher Connection in Open String Field Theory,2602.13627

  52. [54]

    Costello and B

    K. Costello and B. Zwiebach,Hyperbolic String Vertices,JHEP02(2022) 002, [1909.00033]

  53. [55]

    Cho,Open-closed Hyperbolic String Vertices,JHEP05(2020) 046, [1912.00030]

    M. Cho,Open-closed Hyperbolic String Vertices,JHEP05(2020) 046, [1912.00030]

  54. [56]

    Faroogh Moosavian and R

    S. Faroogh Moosavian and R. Pius,Hyperbolic geometry and closed bosonic string field theory. II. The rules for evaluating the quantum BV master action,JHEP08(2019) 177, [1708.04977]

  55. [57]

    A. H. Fırat,Hyperbolic three-string vertex,JHEP08(2021) 035, [2102.03936]

  56. [59]

    Saadi and B

    M. Saadi and B. Zwiebach,Closed String Field Theory from Polyhedra,Annals Phys. 192(1989) 213–227

  57. [60]

    Kugo and K

    T. Kugo and K. Suehiro,Nonpolynomial Closed String Field Theory: Action and Its Gauge Invariance,Nucl. Phys. B337(1990) 434–466

  58. [61]

    Sonoda and B

    H. Sonoda and B. Zwiebach,Covariant Closed String Theory Cannot Be Cubic,Nucl. Phys. B336(1990) 185–221

  59. [62]

    A. H. Fırat and N. Valdes-Meller,Topological recursion for hyperbolic string field theory,2409.02982

  60. [63]

    Off-shell Closed String Amplitudes: Towards a Computation of the Tachyon Potential

    A. Belopolsky and B. Zwiebach,Off-shell closed string amplitudes: Towards a computation of the tachyon potential,Nucl. Phys. B442(1995) 494–532, [hep-th/9409015]

  61. [64]

    Closed Bosonic String Field Theory at Quintic Order: Five-Tachyon Contact Term and Dilaton Theorem

    N. Moeller,Closed Bosonic String Field Theory at Quintic Order: Five-Tachyon Contact Term and Dilaton Theorem,JHEP03(2007) 043, [hep-th/0609209]

  62. [65]

    Closed String Field Theory: Quantum Action and the BV Master Equation

    B. Zwiebach,Closed string field theory: Quantum action and the B-V master equation, Nucl. Phys. B390(1993) 33–152, [hep-th/9206084]

  63. [66]

    de Lacroix, H

    C. de Lacroix, H. Erbin, S. P. Kashyap, A. Sen and M. Verma,Closed Superstring Field Theory and its Applications,Int. J. Mod. Phys. A32(2017) 1730021, [1703.06410]

  64. [67]

    Sen,Off-shell Amplitudes in Superstring Theory,Fortsch

    A. Sen,Off-shell Amplitudes in Superstring Theory,Fortsch. Phys.63(2015) 149–188, [1408.0571]

  65. [68]

    Erbin and A

    H. Erbin and A. H. Fırat,Characterizing 4-string contact interaction using machine learning,JHEP04(2024) 016, [2211.09129]

  66. [69]

    A. H. Fırat,Bootstrapping closed string field theory,JHEP05(2023) 186, [2302.12843]

  67. [70]

    Headrick and B

    M. Headrick and B. Zwiebach,Convex Programs for Minimal-Area Problems, Commun. Math. Phys.377(2020) 2217–2285, [1806.00449]

  68. [71]

    A. H. Fırat,String vertices for the large N limit,Nucl. Phys. B1000(2024) 116485, [2311.00747]

  69. [72]

    S. A. Wolpert,The Weil-Petersson metric geometry,Handbook of Teichm¨ uller Theory 2(2009) 47–64

  70. [73]

    Mirzakhani,Simple geodesics and Weil-Petersson volumes of moduli spaces of bordered Riemann surfaces,Invent

    M. Mirzakhani,Simple geodesics and Weil-Petersson volumes of moduli spaces of bordered Riemann surfaces,Invent. Math.167(2007) 179–222

  71. [74]

    Invariants of algebraic curves and topological expansion

    B. Eynard and N. Orantin,Invariants of algebraic curves and topological expansion, Commun. Num. Theor. Phys.1(2007) 347–452, [math-ph/0702045]

  72. [75]

    J. E. Andersen, G. Borot and N. Orantin,Geometric recursion,arXiv preprint arXiv:1711.04729(2017) . 47