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Courant Algebroid Relations, T-Dualities and Generalised Ricci Flow

T0 review · 2 major / 4 minor · reviewed 2026-08-09 · deepseek-v4-flash

Pith's one-line read The paper proves that geometric T-duality between Courant algebroids is compatible with generalized Ricci flow: the T-dual of a solution is again a solution, and string background equations are preserved.

desk verdict The paper's relational framework for divergences is new and valuable, but the proof of the flow-compatibility theorem has a genuine gap about persistence of the isometry algebra. read the letter →

arxiv 2502.02318 v2 pith:DKUMJYHU submitted 2025-02-04 hep-th math-phmath.DGmath.MP

classification hep-thmath-phmath.DGmath.MP MSC 53D1853C4453C8081T30
keywords CourantalgebroidsT-dualitydivergenceoperatorsgeneralizedRicciflowstringbackgroundequationsdilatonshiftBuscherrulesgeometry
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 aims to prove that geometric T-duality, the equivalence between seemingly different string backgrounds, is compatible with the generalized Ricci flow that governs one-loop renormalization in string sigma-models. The authors use Courant algebroid relations as a notion of morphism, define when divergence operators on two Courant algebroids are related, and show that under natural invariance assumptions a divergence on one side of a T-duality uniquely determines a divergence on the other. From this they prove that related generalized Ricci tensors and scalar curvatures remain related, so T-duality maps solutions of the generalized string background equations to solutions. The main theorem states that if a unique generalized Ricci flow solution exists on one side with complete isometry vector fields, then a unique T-dual family solves the flow on the other side over the same time interval. In physical terms, the claim is that T-duality and the one-loop renormalization group flow commute.

What carries the argument

The carrying object is the Courant algebroid relation $R$, an involutive maximally isotropic (Dirac) subbundle of the product $E_1 \times \overline{E_2}$ with reflected pairing on $E_2$, together with the $\sigma$-adjoint action $\mathrm{ad}^\sigma_X(e) = \llbracket X, e \rrbracket - \rho^* \sigma^* \llbracket X, \sigma\rho(e) \rrbracket$ that cancels the contribution of the twisting class of the exact Courant algebroid to infinitesimal symmetries. Two divergence operators are $R$-related when their values agree along sections of $R$; a generalized isometry is a relation preserved by the two generalized metrics. These notions let the paper define $D_1$-invariant sections and compatible divergences, prove a unique T-dual divergence exists, and show that the generalized Ricci tensor and scalar curvature are relation-preserving, which yields the T-duality of the flow.

What would settle it

For a concrete T-dual pair of the type in Section 5, compute whether the vector fields generating the isometry distribution remain Killing for the evolved metric at every time, and whether the evolved divergence satisfies the compatibility condition with the sigma-adjoint action at every time. If any time is found where the isometry algebra strictly shrinks or compatibility fails, the T-dual family cannot be constructed by this method, contradicting the theorem.

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Extended reading notes

Core claim

The central claim is that a Courant algebroid relation which is at once a Dirac structure and a generalized isometry acts as a transport mechanism for the entire generalized-geometric data: it carries divergence operators, generalized Ricci tensors, generalized scalar curvature, and solutions of the generalized Ricci flow from one exact Courant algebroid to its T-dual. Concretely, Theorem 3.34 gives existence and uniqueness of a T-dual divergence operator under compatibility and spanning assumptions; Theorem 4.11 shows that a D1-invariant solution of the generalized string background equations is transported to a solution; and Theorem 4.14 asserts that a unique generalized Ricci flow with initial pair $(\tau_1, \mathrm{div}_1)$ and complete isometry algebra $\mathfrak{k}_{\tau_1}$ determines a unique T-dual flow. The fixed points of the flow, the generalized string backgrounds, are therefore preserved by geometric T-duality.

Load-bearing premise

The load-bearing premise is that the isometry algebra of the initial generalized metric survives the entire flow, so that the associated divergence operator stays compatible with the same distribution at every time and the T-dual construction can be performed pointwise in time.

Editorial extensions

If this is right

  • A unique generalized Ricci flow on one side of a geometric T-duality with complete Killing fields yields a unique generalized Ricci flow on the other side over the same time interval.
  • Fixed points of the flow, i.e. solutions of the generalized string background equations, are preserved by T-duality, and generalized Einstein pairs are mapped to generalized Einstein pairs.
  • The dilaton shift under T-duality is a consequence of related divergence operators rather than an extra choice.
  • The framework recovers the known T-duality of flows for principal torus bundles and includes new examples such as Klein-bottle fibrations and non-principal circle bundles.
  • Ricci-Buscher rules for the T-dual metric follow from relation-preservation of generalized Ricci tensors, providing direct calculational formulas.

Reading between the lines

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

  • One could test the completeness and persistence hypotheses in the worked examples by checking whether the isometry group of the initial metric is preserved by the evolved metrics and whether the evolved divergence remains compatible with the same distribution; the theorem predicts it is.
  • The same relational machinery might be extended to two-loop or higher-loop renormalization group flow by requiring the Courant algebroid relation to preserve the relevant quantum corrections, though the paper only addresses one-loop.
  • A natural converse question, not addressed here, is whether every T-dual pair of generalized Ricci flows must arise from a Dirac-type relation, or whether more general relations produce additional flow dualities.
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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 / 4 minor

Summary. This paper develops a relational framework for divergence operators on exact Courant algebroids and applies it to geometric T-duality and generalised Ricci flow. The paper introduces R-related divergence operators (Definition 3.7), proves well-definedness and uniqueness (Lemmas 3.8 and 3.18), relates divergences coming from related connections (Proposition 3.21), derives the dilaton shift from related divergences (Section 3.2.2, Equation 3.22), defines invariant sections and D-compatible divergences through the sigma-adjoint action (Definitions 3.24 and 3.26), and proves an existence-uniqueness theorem for T-dual divergence operators (Theorem 3.34) via the lift of D1-invariant sections to K2-basic sections (Lemma 3.32). In Section 4 the paper proves that generalised isometries with related divergences relate generalised Ricci tensors and scalar curvatures (Proposition 4.9), that geometric T-duality preserves the generalised string background equations (Theorem 4.11), that the T-dual of a generalised Ricci flow solution is again a generalised Ricci flow solution (Theorem 4.14), and gives a local version (Theorem 4.16) together with a correspondence-space treatment recovering results for torus bundles. Section 5 constructs explicit examples, including geometric T-duality for Hamilton's cigar soliton, hyperbolic 3-space with H-flux, a self-dual Klein bottle, and a topology-changing Klein bottle fibration.

Significance. Assuming the main theorems survive the repair indicated below, this is a valuable and largely self-contained contribution to the Courant-algebroid approach to T-duality. The proofs are constructive with explicit hypotheses, the R-related divergence formalism (Definition 3.7) gives a genuine mechanism for transporting dilaton data, the dilaton shift is derived rather than imposed (Equation 3.22), and Theorem 3.34 is an honest existence-uniqueness result. The examples are a real strength: they go beyond principal torus bundles and Poisson-Lie T-duality, and the cigar-soliton and hyperbolic-space flows are explicit and checkable. The paper's central claim, compatibility of geometric T-duality with the one-loop generalised Ricci flow, is plausible and consistent with the examples, but Theorem 4.14 requires an additional hypothesis before that claim is proven as stated; the gap is local and fixable within the manuscript's framework.

major comments (2)
  1. [Section 4.4 (proof of Theorem 4.14)] The step 'we may take k_{τ1}(t) := k_{τ1}, for which div1(t) is compatible' is not justified as written. The uniqueness argument only shows that the one-parameter group Φ_s generated by X ∈ k_{τ1} preserves (τ1(t), div1(t)) for every t in the sense of pullback by Courant automorphisms, whereas Definitions 2.32 and 3.26 formulate D1-invariance and D1-compatibility through the σ1-adjoint action ad^{σ1}_X taken with respect to a fixed adapted splitting σ1. By Lemma A.4, ad^{σ1}_X is a derivation of the Dorfman bracket — and hence, by Lemma A.5, the infinitesimal generator of a genuine Courant automorphism — only if ι_X H_1 is closed, where H_1 is the representative of the Ševera class of E1 determined by σ1; the proof neither states this condition nor shows that it follows from the hypotheses of Theorems 2.36 and 3.34. Without it, Φ_s-preservation of div1(t) does not imply the compatibility identity £_X div1(t) e = div1(t) ad^{σ1}_X e, and Theorem 3.34 may not be applicable at each time. The theorem is rescued by adding the hypothesis that every X ∈ k_{τ1} satisfies £_X H_1 = 0 (equivalently, ι_X H_1 is closed); this holds in all examples in Section 5 (H_1 = 0 for the cigar and Klein bottle, and d(ι_{∂θ1} H_1) = 0 in §5.2.1). As stated, this is a load-bearing gap in the paper's central claim.
  2. [Section 4.4 (proof of Theorem 4.14)] The proof also uses the pullback of a divergence operator by a one-parameter group of automorphisms of a single Courant algebroid, together with the naturality identities GRic_{Φ*τ, Φ*div} = Φ* GRic_{τ,div} and GR_{Φ*τ, Φ*div} = Φ* GR_{τ,div}, but none of these operations is defined or proved in the manuscript. Example 3.9 treats isomorphisms between two different Courant algebroids and Example 3.11 treats Courant algebroid morphisms, which is not the same as the pullback along Φ_s : E1 → E1 used in the proof. Since Theorem 4.16 obtains by instead assuming D1-invariance of the solution for all t, the distinctive content of Theorem 4.14 is precisely this persistence argument; the authors should either define the pullback of a divergence explicitly and prove the naturality statements, or add the corresponding invariance-at-each-time hypothesis to the statement of the theorem.
minor comments (4)
  1. [Example 3.43 (§3.4.2)] The displayed identities div_{μg1} e1 = √g^{-1} £_{ρ1(e1)}√g and div_{μg2} e2 = √g £_{ρ2(e2)}√(g^{-1}), asserted 'for all ei ∈ Γ(TQi)', omit the Lie-derivative terms acting on the connection one-forms θi inside the densities |θi ∧ μgB|; for horizontal vector fields these terms involve the curvature of θi. The subsequent dilaton-shift conclusion (ηdil = d log g) is unaffected, but the identities should be restricted to vector fields preserving θi, or amended.
  2. [Section 5] The hypotheses of Theorem 3.34 that Γ_{D1}(E1) spans E1 pointwise and that k_{τ1} spans D1 pointwise are asserted rather than verified in the examples. Section 5.3.2 explicitly lists spanning basic sections for the Klein bottle, but the corresponding checks for §5.1, §5.2 and §5.4 are left implicit; for instance, in §5.2.1 sections such as ∂r + h r θ1 dz are needed alongside the rotationally invariant ones because ad^{σ1}_{∂θ1} contains the ι_Y ι_{∂θ1} H1 term. A brief verification for each example would rule out silent failure of the pointwise spanning hypothesis.
  3. [Appendix A (Lemma A.5)] The identity [ad^σ_X, ad^σ_Y] = ad^σ_{[X,Y]} is deferred to 'various Cartan calculus identities' and the closedness of ι_{[X,Y]} H; since Lemma A.5 underpins the integration argument used in Theorem 4.14, writing out this computation, as is done for Lemma A.4, would make the appendix self-contained.
  4. [Definition 3.7 and Lemma 3.8] In the proof of Lemma 3.8 the divergence on the product algebroid E1 × E2 is written as (div1, div2), but div1 and div2 are only defined on sections of E1 and E2 respectively; the intended formula ~div(e1, e2) := (pr1* div1 e1, pr2* div2 e2), or an explicit statement that sections of R are identified with pairs of pullback sections, should be made explicit.

Circularity Check

0 steps flagged · score 1.0 of 10

No significant circularity: central results are derived from stated geometric hypotheses; reliance on the authors' prior theorems is independent support, not a definitional reduction.

full rationale

This is a pure mathematics construction paper with no fitted parameters and no data-fitting step. Theorems 3.34 and 4.11 are proven from the stated geometric hypotheses; the dilaton shift is derived as Equation (3.22) from R-relatedness rather than imposed. Theorem 4.14 is derived by combining the existing T-duality metric theorem, the new divergence-relation theorem, and the naturality/uniqueness of generalized Ricci flow. The heaviest self-citation burden is Theorem 2.36 and Proposition 5.31 from the authors' earlier paper [13], and these are indeed load-bearing for the T-duality constructions. However, they are independent mathematical theorems proved in [13] under stated assumptions that do not include the target result of the present paper, so they count as genuine evidence rather than circularity under the stated rules. The proof of Theorem 4.14 contains an unproven assertion that the isometry algebra and D1-compatibility persist along the flow ('we may take kτ1(t) := kτ1, for which div1(t) is compatible'); this is a real gap in justification, but it is not a circular reduction because the conclusion is not defined into the hypotheses and no equation is being used as its own input. No circular step of the enumerated kinds was found.

Assumptions & free parameters 0 free parameters · 6 assumptions · 2 invented entities

The central claim rests on the relational T-duality framework of the same authors' prior work [13], on the flow existence results of [11], and on the standing geometric hypotheses of Theorems 2.36 and 3.34 (compatible adapted splittings, K1 intersect K2 = {0}, D1-invariant sections spanning pointwise). These hypotheses are stated explicitly and are natural in the examples, but they are genuine restrictions: the results only apply to T-dualities admitting a simultaneous generalized isometry with complete isometry algebra. No parameters are fitted; the dilaton shift is derived. The sigma-adjoint action is an invented device (introduced in [13]) used to define invariance in the absence of a group action.

assumptions (6)
  • domain assumption Existence and uniqueness of generalized Ricci flow solutions for compact manifolds (Streets-Strickland-Constable-Valach [11]).
    Invoked in the proof of Theorem 4.14 and Corollary 4.15: uniqueness of the flow is used to conclude that Killing fields of the initial data are Killing fields for all times. Proven in the cited paper, not re-proven here.
  • domain assumption The relational T-duality framework of the same authors' prior paper [13]: Theorem 2.36 (existence and uniqueness of the T-dual generalized metric) and Proposition 5.31 (unique splitting with im(s1) contained in K1^perp intersect K2^perp).
    Theorem 3.34 and Theorem 4.14 assume this framework. Lemma 3.32 and the proof of Theorem 3.34 cite [13, Proposition 5.31]; Theorem 2.36 supplies the T-dual metric used throughout Section 4. This is a same-author prior result, peer-reviewed and published in Commun. Math. Phys. 406 (2025) 21.
  • domain assumption K1 intersect K2 = {0} and the space of D1-invariant sections Gamma_D1(E1) spans E1 pointwise (hypotheses of Theorem 3.34).
    These hypotheses make Lemma 3.32 (invariant sections lift to K2-basic sections) and the extension argument in Theorem 3.34 work. They are stated explicitly and verified implicitly in the examples, but their scope is not analyzed; the splitting-dependence of D1-invariance is acknowledged in Remark 3.25.
  • domain assumption Bisubmersion involutivity (Equation 2.37) and existence of compatible adapted splittings (Definitions 2.34 and 2.40).
    Conditions from [13] guaranteeing that the T-duality relation R is a well-defined Courant algebroid relation and a generalized isometry. The paper inherits them without re-derivation.
  • standard math Standard Courant algebroid background: Definition 2.1, reduction theorem 2.14 (Bursztyn-Cavalcanti-Gualtieri-Zambon), and Severa classification of exact Courant algebroids by a class [H] in H3(M,R).
    Background material from [1-4, 14, 35-37]; taken as established mathematics.
  • domain assumption Hausdorff-Morita equivalence of the foliations F1 and F2 under condition (2.37), cited from [38].
    Used to identify the base of the fibred product and the module isomorphisms in Proposition 3.38; cited from [38] without proof.
invented entities (2)
  • sigma-adjoint action ad_sigma on exact Courant algebroids (Equation 2.31).
    purpose: Defines D1-invariance of generalized metrics (Definition 2.32) and of sections (Definition 3.24), and D1-compatibility of divergence operators (Definition 3.26), without requiring a Lie group action on the Courant algebroid. It is the technical backbone of all invariance hypotheses.
    Introduced in the same authors' prior work [13, Definition 5.21] and developed further in Appendix A (Lemmas A.1-A.9). It is a mathematical device whose validity rests on internal consistency and on the theorems it enables; there is no falsifiable handle outside the paper.
  • R-related divergence operators and the T-dual divergence operator (Definition 3.7, Theorem 3.34).
    purpose: A new morphism notion for divergence operators, encoding the dilaton shift as the failure of volume-form divergences to be R-related (Equation 3.22, Definition 3.23).
    New definitions introduced in this paper; they are mathematical constructs, not physical entities, and their justification is the resulting existence and uniqueness theorem and the flow compatibility theorem.

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Pith. "Pith review of Courant Algebroid Relations, T-Dualities and Generalised Ricci Flow." pith.science (2026). https://pith.science/paper/DKUMJYHU

@misc{pith2026250202318,
  author       = {Pith},
  title        = {Pith review of: Courant Algebroid Relations, T-Dualities and Generalised Ricci Flow},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/DKUMJYHU}},
  note         = {Machine review of arXiv:2502.02318}
}
read the original abstract

The notion of Courant algebroid relation is used to introduce a definition of relation between divergence operators on Courant algebroids. By introducing invariant divergence operators, a notion of generalised T-duality between divergences is presented through an existence and uniqueness result for related divergence operators on T-dual pairs of exact Courant algebroids, which naturally incorporates the dilaton shift. When combined with the notion of generalised isometry, this establishes circumstances under which generalised Ricci tensors are related, proving that T-duality is compatible with generalised string background equations. This enables an analysis of the compatibility between T-duality and generalised Ricci flow, showing that the T-dual of a solution of generalised Ricci flow is also a solution of generalised Ricci flow. Our constructions are illustrated through many explicit examples.

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Reference graph

Works this paper leans on

44 extracted references · 20 canonical work pages

  1. [13]

    T. C. De Fraja, V. E. Marotta and R. J. Szabo, T-Dualities and Courant Algebroid Relations , Commun. Math. Phys. 406 (2025) 21 [ 2308.15147]

  2. [1]

    Z.-J. Liu, A. Weinstein and P. Xu, Manin triples for Lie bialgebroids , J. Diff. Geom. 45 (1997) 547 [dg-ga/9508013]

  3. [2]

    T. J. Courant, Dirac Manifolds , Trans. Amer. Math. Soc. 319 (1990) 631

  4. [3]

    Hitchin, Generalized Calabi-Yau manifolds , Quart

    N. Hitchin, Generalized Calabi-Yau manifolds , Quart. J. Math. 54 (2003) 281 [ math/0209099]

  5. [4]

    Gualtieri, Generalized Complex Geometry , Ph.D

    M. Gualtieri, Generalized Complex Geometry , Ph.D. thesis, University of Oxford, 2003. math.DG/0401221

  6. [5]

    Li-Bland and E

    D. Li-Bland and E. Meinrenken, Courant Algebroids and Poisson Geometry , Int. Math. Res. Not. 2009 (2009) 2106 [ 0811.4554]

  7. [6]

    Dirac Lie Groups

    D. Li-Bland and E. Meinrenken, Dirac Lie Groups , Asian J. Math. 18 (2014) 779 [ 1110.1525]

  8. [7]

    Vysoký, Hitchhiker’s Guide to Courant Algebroid Relations , J

    J. Vysoký, Hitchhiker’s Guide to Courant Algebroid Relations , J. Geom. Phys. 151 (2020) 103635 [ 1910.05347]

Show all 44 references
  1. [8]

    Roytenberg, On the structure of graded symplectic supermanifolds and Co urant algebroids, Contemp

    D. Roytenberg, On the structure of graded symplectic supermanifolds and Co urant algebroids, Contemp. Math. 315 (2002) 169 [ math/0203110]

  2. [9]

    Gualtieri, Branes on Poisson varieties , in The Many Facets of Geometry: A Tribute to Nigel Hitchin , pp

    M. Gualtieri, Branes on Poisson varieties , in The Many Facets of Geometry: A Tribute to Nigel Hitchin , pp. 368–394, Oxford University Press, 2010, [ 0710.2719]

  3. [10]

    Garcia-Fernandez and J

    M. Garcia-Fernandez and J. Streets, Generalized Ricci Flow . American Mathematical Society, 2021, [2008.07004]

  4. [11]

    Streets, C

    J. Streets, C. Strickland-Constable and F. Valach, Ricci flow on Courant algebroids , 2402.11069

  5. [12]

    Garcia-Fernandez, Ricci flow, Killing spinors, and T-duality in generalized ge ometry, Adv

    M. Garcia-Fernandez, Ricci flow, Killing spinors, and T-duality in generalized ge ometry, Adv. Math. 350 (2019) 1059 [ 1611.08926]

  6. [14]

    Ševera, Letters to Alan Weinstein about Courant Algebroids , 1707.00265

    P. Ševera, Letters to Alan Weinstein about Courant Algebroids , 1707.00265

  7. [15]

    Ševera, Poisson-Lie T-Duality and Courant Algebroids , Lett

    P. Ševera, Poisson-Lie T-Duality and Courant Algebroids , Lett. Math. Phys. 105 (2015) 1689 [ 1502.04517]

  8. [16]

    C. M. Hull and R. A. Reid-Edwards, Non-geometric backgrounds, doubled geometry and generali zed T-duality , JHEP 09 (2009) 014 [ 0902.4032]

  9. [17]

    V. E. Marotta and R. J. Szabo, Born Sigma-models for Para-Hermitian Manifolds and Genera lized T-duality , Rev. Math. Phys. 33 (2021) 2150031 [ 1910.09997]

  10. [18]

    G. R. Cavalcanti and M. Gualtieri, Generalized complex geometry and T-duality , in A Celebration of the Mathematical Legacy of Raoul Bott , pp. 341–366, American Mathematical Society, 2010, [ 1106.1747]

  11. [19]

    T. C. De Fraja, V. E. Marotta and R. J. Szabo, Generalised Complex and Spinor Relations , in preparation

  12. [20]

    Klimčík and P

    C. Klimčík and P. Ševera, Dual non-abelian duality and the Drinfel’d double , Phys. Lett. B 351 (1995) 455 [hep-th/9502122]

  13. [21]

    Klimčik and P

    C. Klimčik and P. Ševera, Dressing cosets, Phys. Lett. B 381 (1996) 56 [ hep-th/9602162]

  14. [22]

    Ševera, Poisson-Lie T-duality as a boundary phenomenon of Chern-Si mons theory, JHEP 05 (2016) 044 [1602.05126]

    P. Ševera, Poisson-Lie T-duality as a boundary phenomenon of Chern-Si mons theory, JHEP 05 (2016) 044 [1602.05126]

  15. [23]

    Ševera and F

    P. Ševera and F. Valach, Courant Algebroids, Poisson–Lie T-Duality, and Type II Sup ergravities, Commun. Math. Phys. 375 (2020) 307 [ 1810.07763]

  16. [24]

    Chow and D

    B. Chow and D. Knopf, The Ricci Flow: An Introduction . American Mathematical Society, 2004

  17. [25]

    Baraglia and P

    D. Baraglia and P. Hekmati, Transitive Courant Algebroids, String Structures and T-du ality, Adv. Theor. Math. Phys. 19 (2015) 613 [ 1308.5159]

  18. [26]

    Streets, Generalized geometry, T-duality, and renormalization gro up flow , J

    J. Streets, Generalized geometry, T-duality, and renormalization gro up flow , J. Geom. Phys. 114 (2017) 506 [1310.5121]

  19. [27]

    Ševera and F

    P. Ševera and F. Valach, Ricci flow, Courant algebroids, and renormalization of Pois son–Lie T-duality , Lett. Math. Phys. 107 (2017) 1823 [ 1610.09004]

  20. [28]

    Pulmann, P

    J. Pulmann, P. Ševera and D. R. Youmans, Renormalization group flow of Chern-Simons boundary condit ions and generalized Ricci tensor , JHEP 10 (2020) 096 [ 2009.00509]. COURANT ALGEBROID RELATIONS, T-DUALITIES AND GENERALISED RICCI FLOW 49

  21. [29]

    C. G. Callan, Jr., E. J. Martinec, M. J. Perry and D. Fried an, Strings in Background Fields , Nucl. Phys. B 262 (1985) 593

  22. [30]

    Oliynyk, V

    T. Oliynyk, V. Suneeta and E. Woolgar, A Gradient flow for worldsheet nonlinear sigma models , Nucl. Phys. B 739 (2006) 441 [ hep-th/0510239]

  23. [31]

    Hassler and T

    F. Hassler and T. B. Rochais, O(D, D )-covariant two-loop β -functions and Poisson-Lie T-duality , JHEP 10 (2021) 210 [ 2011.15130]

  24. [32]

    Jurčo and J

    B. Jurčo and J. Vysoký, Courant Algebroid Connections and String Effective Actions , in Workshop on Strings, Membranes and Topological Field Theory , pp. 211–265, World Scientific Publishing Company, 2016, [1612.01540]

  25. [33]

    G. R. Cavalcanti, J. Pedregal and R. Rubio, On the Equivalence of Generalized Ricci Curvatures , 2406.06695

  26. [34]

    Bouwknegt, K

    P. Bouwknegt, K. Hannabuss and V. Mathai, T-duality for principal torus bundles , JHEP 03 (2004) 018 [hep-th/0312284]

  27. [35]

    Zambon, Reduction of branes in generalized complex geometry , J

    M. Zambon, Reduction of branes in generalized complex geometry , J. Sympl. Geom. 6 (2008) 353 [math/0701740]

  28. [36]

    Bursztyn, G

    H. Bursztyn, G. R. Cavalcanti and M. Gualtieri, Reduction of Courant algebroids and generalized complex structures, Adv. Math. 211 (2007) 726 [ math/0509640]

  29. [37]

    Bursztyn, A

    H. Bursztyn, A. S. Cattaneo, R. A. Mehta and M. Zambon, Graded geometry and generalized reduction , 2306.01508

  30. [38]

    Garmendia and M

    A. Garmendia and M. Zambon, Hausdorff Morita equivalence of singular foliations , Ann. Glob. Anal. Geom. 55 (2019) 99 [ 1803.00896]

  31. [39]

    Alekseev and P

    A. Alekseev and P. Xu, Derived Brackets and Courant Algebroids , Unpublished (2001)

  32. [40]

    Jurčo and J

    B. Jurčo and J. Vysoký, Poisson-Lie T-duality of string effective actions: A new app roach to the dilaton puzzle , J. Geom. Phys. 130 (2018) 1 [ 1708.04079]

  33. [41]

    Bouwknegt, J

    P. Bouwknegt, J. Evslin and V. Mathai, T duality: Topology change from H flux , Commun. Math. Phys. 249 (2004) 383 [ hep-th/0306062]

  34. [42]

    Lambert and V

    C. Lambert and V. Suneeta, Stability analysis of the Witten black hole (cigar soliton) under world-sheet RG flow , Phys. Rev. D 86 (2012) 084041 [ 1205.3043]

  35. [43]

    Paradiso, Generalized Ricci flow on nilpotent Lie groups , Forum Math

    F. Paradiso, Generalized Ricci flow on nilpotent Lie groups , Forum Math. 33 (2021) 997 [ 2002.01514]

  36. [44]

    Baraglia, Topological T-duality for general circle bundles , Pure Appl

    D. Baraglia, Topological T-duality for general circle bundles , Pure Appl. Math. Quart. 10 (2014) 367 [1105.0290]. (Thomas C. De Fraja) Depar tment of Ma thema tics and Maxwell Institute for Ma them a tical Sci- ences, Heriot-W a tt University, Edinburgh EH14 4AS, United Kingd...

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