Pith. sign in

REVIEW 2 major objections 5 minor 1 cited by

On the initial geometry of a vacuum cosmological spacetime

T0 review · 2 major / 5 minor · reviewed 2026-08-14 · deepseek-v4-flash

Pith's one-line read This paper establishes that Gowdy vacuum spacetimes have AVTD-like initial geometry in any dimension, measured in a spike-tolerant $H^{-1}$ norm, and gives sufficient conditions for the same behavior in four-dimensional $T^2$-invariant…

desk verdict A well-crafted paper with a real new AVTD estimate for Gowdy spacetimes in arbitrary dimension, conditional on an areal-time assumption that is not proved, plus solid Section 3 results and one omitted proof that needs attention. read the letter →

arxiv 1908.02185 v3 pith:PX7TVQTM submitted 2019-08-06 math.DG gr-qc

classification math.DGgr-qc MSC 53C5083C0535Q75
keywords GowdyspacetimeAVTDbehaviorT^NsymmetrycrushingsingularityCMCEinsteinflowKasnersolutionH^{-1}Sobolevnormcausalpasts
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 studies what happens to the geometry of an expanding vacuum universe as its spatial slices collapse toward the initial singularity at $t=0$. Its central claim is that Gowdy spacetimes—vacuum spacetimes with a free torus symmetry and integrable normal distribution—are asymptotically velocity term dominated in every dimension: in a suitable averaged Sobolev sense, the matrix $G$ describing the torus metric approaches a solution of the velocity term dominated equations exponentially fast in the logarithmic time $\tau=-\log t$. Because the decay is measured in an $H^{-1}$ norm, it tolerates the spikes that are known to occur in Gowdy solutions. The paper also proves an analogous averaged AVTD statement for four-dimensional $T^2$-invariant non-Gowdy spacetimes under two explicit conditions, and, in the symmetry-free setting of constant-mean-curvature Einstein flows with a crushing singularity, introduces a monotone normalized volume whose equality case characterizes Kasner solutions and whose consequences include statements about normalized diameters and disjoint causal pasts near the singularity.

What carries the argument

The argument is carried by monotone functionals whose derivatives are positive integrals of spatial derivative terms. For Gowdy spacetimes, the quantity $\tilde E(t)=\frac{\sqrt{\det G}}{(\ln\det G)_t}E(t)$ has time derivative $\frac{d\tilde E}{dt}=\sqrt{\det G}\int_Y Lh^{-1}\operatorname{Tr}((G^{-1}G_y)^2)\,d\mathrm{vol}$, turning the standard energy $E(t)$ into a quantity that increases toward the singularity; the same structure produces the weight $e^{N\tau}$ and the $H^{-1}_{Y,\tau}$ norm after the change $t=e^{-\tau}$. For the non-Gowdy case, $\tilde E_K=R^2\hat E_K+\frac12 K\int_Y H\,d\theta$ has derivative $2R\int_Y(aU_\theta^2+\frac14 R^{-2}e^{4U}a^{-1}A_R^2)\,d\theta$, which yields the condition (1.7). In the CMC part, the normalized volume $(-H)\operatorname{vol}(X,h(t))=t^{-1}\operatorname{vol}(X,h(t))$ differentiates to $-\frac13\int_X LR\,d\mathrm{vol}_h$, so under $R\le 0$ it is monotonically nondecreasing; equality forces $L=\frac1{H^2}\partial_t H$, $R=0$ and $|K|^2=H^2$, and with an aspherical prime component this is a Kasner solution.

What would settle it

Construct a twisted $T^N$ Gowdy vacuum spacetime whose flat bundle has holonomy outside $SL(N,\mathbb{R})$, or for which no global areal time coordinate with spatially constant $\det G$ exists, and show that the integral in (2.44) diverges; alternatively, exhibit a $T^2$-invariant four-dimensional solution with $\int_Y H\,d\theta$ bounded below and $e^{4U}a^2A_\theta^2\in H$ for which $a(a^{-1}U_\tau)_\tau-\frac12 e^{2\tau}e^{4U}A_\tau^2\notin H$, contradicting Proposition 2.65.

Watch

Extended reading notes

Core claim

The main discovery is that $G$-component AVTD behavior holds for all Gowdy vacuum spacetimes in arbitrary dimension, in an integrated sense. After choosing areal time with $\det G=t^N$ and setting $t=e^{-\tau}$, the paper proves (Theorem 1.3) that $$\int_{\tau_0}^{\infty} $e^{{N\tau}}$\|($G^{{-1}}$G_\tau)_\tau\|^2_{$H^{{-1}}$_{Y,\tau}}\,d\tau<\infty.$$ The $H^{-1}$ norm is taken over the spatial circle with respect to a $t$-independent density $\mu$, and the weight $e^{N\tau}$ gives exponential decay of the velocity-term error $(G^{-1}G_\tau)_\tau$ in this averaged sense as $\tau\to\infty$. The statement is spike-tolerant: pointwise limits may be irregular, but the averaged derivative is coercively controlled. The proof uses a monotone energy $\tilde E(t)$ whose time derivative is a positive integral of a spatial derivative term; after integrating by parts and applying Cauchy-Schwarz, this becomes the dual $H^{-1}$ estimate. For four-dimensional $T^2$-invariant non-Gowdy spacetimes, Proposition 2.65 gives a sufficient condition for the analogous AVTD statement for $U$: if $\int_Y H\,d\theta$ is bounded below and $e^{4U}a^2A_\theta^2$ lies in the same weighted $H^{-1}$ space, then $a(a^{-1}U_\tau)_\tau-\tfrac12 e^{2\tau}e^{4U}A_\tau^2$ also lies in that space.

Load-bearing premise

The Gowdy proof assumes a global areal time coordinate in which $\det G=t^N$, with the flat torus bundle having holonomy in $SL(N,\mathbb{R})$; the $t$-independent density $\mu$ and the weight $e^{N\tau}$ are built from that foliation, so if a twisted $T^N$ Gowdy spacetime lacks such a coordinate, the AVTD conclusion of Theorem 1.3 does not follow in that setting.

Editorial extensions

If this is right

  • Any Gowdy vacuum spacetime in any dimension has an averaged AVTD property: the $G$-component's velocity-term error decays exponentially in $\tau$ when measured in the weighted $H^{-1}$ norm, even if spikes prevent pointwise decay.
  • The half-polarized $T^2$-invariant solutions constructed by Fuchsian methods satisfy the two hypotheses of Proposition 2.65, so they are covered by the non-Gowdy AVTD statement.
  • For constant-mean-curvature Einstein flows with $R\le 0$, the normalized volume $t^{-1}\operatorname{vol}$ is monotone and its equality case is a Kasner solution, giving a clean geometric characterization of the extremal approach to the singularity.
  • Noncollapsed type-I Einstein flows are rigid in the sense that either they are Lorentzian cones over compact hyperbolic 3-manifolds, or their normalized diameters diverge and one can find many points whose causal pasts are mutually disjoint on the time interval $[\Lambda^{-1}t,t]$.
  • Localizing the causal-past statement gives a dichotomy on any open set: near the singularity the rescaled flow is close to a hyperbolic cone, or many mutually disjoint causal pasts exist inside that set.

Reading between the lines

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

  • The $H^{-1}$ formulation suggests that pointwise spike behavior is the wrong measurement scale for AVTD; one could test whether explicit spike families saturate the integral in (2.44), which would confirm that the norm captures exactly the right sharpness.
  • The same monotone-functional mechanism may extend to other symmetry classes or to spacetimes with matter, since the paper notes heuristically that matter is often asymptotically irrelevant; a concrete next step would be to find a monotone quantity whose derivative controls the matter terms directly.
  • The line between AVTD and Mixmaster dynamics could be sharpened by determining which of the two hypotheses in Proposition 2.65 fails in numerical Mixmaster $T^2$-symmetric solutions; the paper leaves this question open.
  • Because $t^{-1}\operatorname{vol}$ is not rescaling-invariant, unlike the Fischer-Moncrief quantity, it may encode the asymmetry between the shrinking and expanding directions; testing whether other powers $t^{-\alpha}\operatorname{vol}$ are monotone under weaker curvature assumptions would clarify how special $\alpha=1$ is.
Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

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. The paper studies the geometry of expanding vacuum cosmological spacetimes approaching an initial singularity, in two parts. Part 1 (Section 2) concerns spacetimes with a free T^N action and a two-dimensional orbit space. For Gowdy spacetimes (vanishing connection curvature, F=0, §2.2) with a global areal time coordinate det G = t^N and e-holonomy in SL(N,R), the paper proves Theorem 1.3/Proposition 2.43: ∫_{τ0}^∞ e^{Nτ}||(G^{-1}G_τ)_τ||²_{H^{-1}_{Y,τ}} dτ < ∞, an averaged, spike-robust AVTD-type statement in arbitrary dimension. The proof introduces the monotone quantity E~ (2.20), derives the dual-pairing bound (2.37)-(2.40), and defines the time-dependent H^{-1} norm (2.41). For nonGowdy T²-invariant four-dimensional spacetimes (§2.3), Proposition 2.65 gives a sufficient condition for AVTD behavior of U in the same integral sense. Part 2 (Section 3) treats CMC Einstein flows with crushing singularities: Theorem 1.9 identifies d/dt(t^{-1}vol) = -(1/3)∫LR dvol; Theorem 1.12 characterizes the equality case under R ≤ 0 as a Kasner solution; Theorem 1.13/Proposition 3.48 asserts Kasner-like rescaling limits in L¹ with respect to the limiting measure dvol_0 (proof delegated to [24]); under type-I and noncollapsing assumptions, Theorem 1.15 bounds normalized diameters, Theorems 1.16/1.17 and Proposition 3.73 give causal-past dichotomies, and Proposition 3.78 upgrades the Kasner limit to a pointwise statement.

Significance. Conditional on the global areal-time hypothesis, Theorem 1.3 is a genuine advance: the H^{-1} formulation captures AVTD behavior in an averaged sense while allowing spatial spikes, in arbitrary dimension, whereas previous Gowdy asymptotics (Ringström) were pointwise and N=2. The monotone quantity E~ and the identity dE~/dt (2.21) are elegant and parameter-free, and the dual-space step (2.40)→(2.44) is sound: (2.40) states that (G^{-1}G_τ)_τ is a bounded functional on the weighted H¹ space, which is equivalent to membership in the space H of (2.42). The identities (1.10)/(3.24), the equality case Theorem 1.12, and the type-I diameter and causal-past dichotomies are new and clearly stated. The paper is honest about the limits of the nonGowdy result (discussion after Remark 2.68) and explicitly corrects two equations from [24] (Remark 2.23). The central estimates are derived from the Einstein equations in the paper; no fitted parameters appear and there is no circular dependence on the paper's own conclusions.

major comments (2)
  1. [§2.1 and Theorem 1.3] Theorem 1.3 and the abstract's 'Gowdy spacetimes ... in any dimension' claim are conditional on hypotheses that are introduced inside §2.1 but not proved or referenced for N>2: the existence of a global areal time coordinate with det G = t^N ('As is standard ... c.f. [4]', §2.1) and the assumption that the flat bundle e has holonomy in SL(N,R) (after (2.5)). Reference [4] is a four-dimensional T² paper. These hypotheses are load-bearing: the t-independent density μ of (2.14) is defined only under the areal-time and F=0 assumptions; the weight e^{Nτ} in (2.44) is obtained in (2.38)-(2.39) precisely from det G = t^N; and ln det G is globally defined only under the SL(N,R) holonomy assumption. If the global foliation fails for some twisted T^N Gowdy spacetime, μ, the norm (2.41), and the statement (2.44) are not globally well-defined. I recommend either (a) restating Theorem 1.3 with an explicit hypothesis block containing the areal-time and holonomy conditions and changing the abstract to 'for Gowdy spacetimes admitting a global areal time coordinate with det G = t^N', or (b) adding a proof or literature reference for the existence of such coordinates for free T^N actions with N>2. The stress-test concern lands, though as a scope mismatch rather than an internal inconsistency: the derivation is internally coherent and the assumption is acknowledged in the text, but the advertised claim is broader than the proved claim.
  2. [§3.1, Proposition 3.48] Proposition 3.48 (Theorem 1.13, a headline result of Section 3) is stated with the proof 'The proof is similar to that of [24, Proposition 2.36]. We omit the details.' This delegation is nontrivial for three reasons: the statement concludes L¹ convergence on [Λ^{-1},Λ] × X with respect to du dvol_0, where dvol_0 = lim t→0 (-H)dvol is only a nonnegative absolutely continuous measure that may be zero (Definition 3.47); the quantities |L_s - 1/n| and |K_s|² - n²/u² involve the rescaling (3.44) applied simultaneously to lapse, second fundamental form, and scalar curvature; and dvol_0 is itself obtained from the flow, so it is not immediate that the hypotheses of [24, Prop 2.36] carry over verbatim. Since Theorem 1.13 is advertised in the abstract and presented as a main theorem, I ask that the proof be included, or at least that the author spell out the reduction to [24, Prop 2.36] and verify each hypothesis, including the treatment of the dvol_0 = 0 case. This is a load-bearing gap because the Kasner-type rescaling-limit statement is one of the two central conclusions of Section 3.
minor comments (5)
  1. [Abstract and Theorem 1.3] The notation for the Sobolev space is inconsistent: the abstract and Theorem 1.3 use H^{-1}_τ, while (2.41) defines H^{-1}_{Y,τ}; please harmonize the notation and make clear in the theorem statement that the norm is defined using the density μ from (2.14).
  2. [§2.1, equations (2.37)-(2.38)] The passage from (2.37) to (2.38) silently multiplies both sides by N after substituting det G = t^N (so that (ln det G)_t = N/t); a one-sentence remark would help the reader verify the constant N^{3/2}.
  3. [§3, Proposition 3.37 proof] There is a typo in the proof: 'h^{-1}K satifies' should read 'satisfies'; several similar OCR-style typos occur elsewhere in the manuscript and should be corrected in revision.
  4. [§3.2, Proposition 3.59] The proof of Proposition 3.59 is delegated with 'The proof ... is essentially the same as that of [24, Corollary 2.54]'; a short indication of why type-I and noncollapsing at a sequence of points imply the required uniform local geometry bounds would make the paper more self-contained, given that Proposition 3.59 underlies all of Section 3.4.
  5. [§2.3, Remark 2.68] The verification that the half-polarized condition implies (2.66) is presented heuristically ('e^{4U}a²A_θ² ∼ e^{-2τ}'); a precise pointer to the justification in [1] and to the exact sense of the asymptotics would be helpful, since the sufficient condition (1.7) is a hypothesis of Theorem 1.6.

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the AVTD estimates and monotonic quantities are derived from the vacuum Einstein equations, and cited prior work supplies background or independent technical lemmas.

full rationale

The paper's central derivations are self-contained in the relevant sense. In Section 2, the monotonic functional ~E in (2.20) is constructed from the energy E and the Einstein-equation identity (2.16); differentiating it gives (2.21), whose integral form (2.25) is the only input needed for the duality estimate (2.40). The H^{-1}_{Y,τ} norm (2.41) is then the dual norm that converts (2.40) into the stated bound (2.44). This is a genuine derivation, not a renaming: the estimate (2.40) is obtained from the evolution equation, and no parameter is fitted to the conclusion. The global areal-time and det(G)=t^N assumptions, introduced after (2.5) with the holonomy-in-SL(N,R) condition, are hypotheses taken from the literature, not consequences of Theorem 1.3; they restrict the scope of the theorem but do not make it circular. The nonGowdy result likewise follows by rearranging the identity (2.64), with the condition e^{4U}a^2A^2_θ in H as a genuine sufficient condition rather than a restatement of the conclusion. Section 3's monotonic volume identity (3.24) is computed directly from the CMC evolution equations, and the Kasner characterization uses standard material plus external facts such as the non-existence of positive scalar curvature metrics on aspherical 3-manifolds, Mostow rigidity, and Perelman's work. The citations to the author's own [23] and [24] provide the twisted-bundle formalism, Ricci-tensor formulas, and rescaling-compactness lemmas; these are published technical results with proofs independent of the present theorems, so they do not constitute circularity. The paper itself flags its limitations, including the global areal foliation assumption and the remark that it has nothing to say about Mixmaster dynamics, which confirms that the claims are conditional rather than circular.

Assumptions & free parameters 0 free parameters · 8 assumptions · 0 invented entities

No free parameters are fitted to data; the paper's assumptions are explicit geometric or analytic hypotheses. The monotonic quantities are functionals of the flow, not new physical entities. The most load-bearing axiomatic input is the areal-time coordinate assumption in the Gowdy part, and the type-I/noncollapsed bounds in the causal-past theorems.

assumptions (8)
  • domain assumption Existence of a global areal time coordinate with det(G)=t^N for Gowdy spacetimes.
    Stated in Section 2.1 after (2.9): 'We suppose hereafter that det G is spatially constant, i.e. only depends on t [4].' Used to define the density μ in (2.14) and the exponential weights in (2.38)-(2.44).
  • domain assumption The flat vector bundle e has holonomy in SL(N,R), so ln det G is globally defined.
    Explicitly assumed in Section 2.1 before (2.5); needed for the global formulas for ∇ ln det G and the monotonic quantities in the Gowdy part.
  • domain assumption The spacetime has a crushing singularity and a nearby CMC foliation by compact hypersurfaces.
    Definition 3.7 and Gerhardt's theorem [17] are used in Section 3 to set t = -n/H and to express the metric as -L^2 dt^2 + h(t).
  • domain assumption Spatial scalar curvature R ≤ 0 in Theorems 1.12, 1.13, 3.78 and related corollaries.
    Assumed in the statements to guarantee monotonicity of t^{-1} vol and the listed L^1 Kasner limit.
  • domain assumption Type-I curvature bound |Rm|_T ≤ C t^{-2} and noncollapsing volume bound vol(B_h(x,t)) ≥ v0 t^n.
    Definitions 3.56 and 3.58; assumed for Theorems 1.15-1.17 and Proposition 3.78 to obtain rescaling limits.
  • standard math Schoen-Yau theorem: an orientable aspherical 3-manifold admits no metric of positive scalar curvature.
    Used in the proof of Proposition 3.37 (Theorem 1.12) to conclude the Ricci flow must be Ricci-flat.
  • standard math Strong maximum principle for elliptic/parabolic equations in the lapse and scalar curvature.
    Used in Propositions 3.34, 3.36, and 3.78 to upgrade local equalities to global Kasner-like conclusions.
  • standard math Perelman's Ricci flow theory, including the existence of canonical flows and diameter/volume control.
    Cited via [20] (Kleiner-Lott notes) in Corollary 3.63 to compare normalized volumes with hyperbolic metric volume.

how reviews work

0 comments
Cite this review

Pith. "Pith review of On the initial geometry of a vacuum cosmological spacetime." pith.science (2026). https://pith.science/paper/PX7TVQTM

@misc{pith2026190802185,
  author       = {Pith},
  title        = {Pith review of: On the initial geometry of a vacuum cosmological spacetime},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/PX7TVQTM}},
  note         = {Machine review of arXiv:1908.02185}
}
abstract

In the first part of this paper we consider expanding vacuum cosmological spacetimes with a free $T^N$-action. Among them, we give evidence that Gowdy spacetimes have AVTD (asymptotically velocity term dominated) behavior for their initial geometry, in any dimension. We then give sufficient conditions to reach a similar conclusion about a $T^2$-invariant four dimensional nonGowdy spacetime. In the second part of the paper we consider vacuum cosmological spacetimes with crushing singularities. We introduce a monotonic quantity to characterize Kasner spacetimes. Assuming scale-invariant curvature bounds and local volume bounds, we give results about causal pasts.

Discussion (0). Continue with ORCID to comment.

Forward citations

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 localized construction of Kasner-like singularities

    math.AP 2024-12 conditional novelty 6.0 of 10

    A first order symmetric hyperbolic formulation is used to construct local vacuum Einstein solutions with prescribed Kasner-like singular behavior.

Reference graph

Works this paper leans on

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

  1. [24]

    Collapsing in the Einstein flow

    J. Lott, “Collapsing in the Einstein flow”, Annales Henri Poincare 19, p. 2245-2296 (2018)

  2. [4]

    Global foliations of vacuum spacetimes with T 2 isometry

    B. Berger, P. Chru´ sciel, J. Isenberg and V. Moncrief, “Global foliations of vacuum spacetimes with T 2 isometry”, Ann. Physics 260, p. 117-148 (1997)

  3. [1]

    Quasilinear hyp erbolic Fuchsian systems and A VTD behavior in T 2-symmetric vacuum spacetimes

    E. Ames, F. Beyer, J. Isenberg and P. LeFloch, “Quasilinear hyp erbolic Fuchsian systems and A VTD behavior in T 2-symmetric vacuum spacetimes”, Ann. Henri Poincar´ e 14, p. 144 5-1523 (2013)

  4. [2]

    On long-time evolution in general relativity and geo metrization of 3-manifolds

    M. Anderson, “On long-time evolution in general relativity and geo metrization of 3-manifolds”, Comm. Math. Phys. 222, p. 533-567 (2001)

  5. [3]

    Regularity for Lorentz metrics under curvatur e bounds

    M. Anderson, “Regularity for Lorentz metrics under curvatur e bounds”, J. Math. Phys. 44, p. 2994- 3012 (2003)

  6. [5]

    Phenomenology of the Gowdy univer se on T 3 × R

    B. Berger and D. Garfinkle, “Phenomenology of the Gowdy univer se on T 3 × R”, Phys. Rev. D 57, p. 4767-4777 (1998)

  7. [6]

    Oscillatory approach t o the singularity in vacuum spacetimes with T 2 isometry

    B. Berger, J. Isenberg and M. Weaver, “Oscillatory approach t o the singularity in vacuum spacetimes with T 2 isometry”, Phys. Rev. D 64, 084006 (2001)

  8. [7]

    Numerical investigation of cosmolog ical singularities

    B. Berger and V. Moncrief, “Numerical investigation of cosmolog ical singularities”, Phys. Rev. D 48, p. 4676-4687 (1993)

Show all 30 references
  1. [8]

    Oscillatory approach t o a singular point in the relativistic cosmology

    V. Belinskii, I, Khalatnikov and E. Lifshitz, “Oscillatory approach t o a singular point in the relativistic cosmology”, Adv. Phys. 19, p. 525-573 (1970)

  2. [9]

    Belinski and M

    V. Belinski and M. Henneaux, The cosmological singularity , Cambridge University Press, Cambridge (2017)

  3. [10]

    Bianchi VIII and IX vacuum cosmologies: Almost eve ry solution forms particle horizons and converges to the Mixmaster attractor

    B. Brehm, “Bianchi VIII and IX vacuum cosmologies: Almost eve ry solution forms particle horizons and converges to the Mixmaster attractor”, preprint, https:// arxiv.org/abs/1606.08058 (2016)

  4. [11]

    Local foliations and optimal regular ity of Einstein spacetimes

    B.-L. Chen and P. LeFloch, “Local foliations and optimal regular ity of Einstein spacetimes”, J. Geom Phys. 59, p. 913-941 (2009)

  5. [12]

    Areal foliation and asymptotically velocity-term dominated behavior in T 2 symmetric space-times with positive cosmological constant

    A. Clausen and J. Isenberg, “Areal foliation and asymptotically velocity-term dominated behavior in T 2 symmetric space-times with positive cosmological constant”, J. Ma th. Phys. 48, 082501 (2007)

  6. [13]

    Continuous time dynamics and iteratif e maps of Ellis-MacCallum- Wainwright variables

    T. Creighton and D. Hobill, “Continuous time dynamics and iteratif e maps of Ellis-MacCallum- Wainwright variables”, in Deterministic chaos in general relativity , eds. D. Hobill, A. Burd and A. Coley, NATO ASI Series B: Physics Vol. 332, Springer, New York, p. 4 33-448 (1994)

  7. [14]

    Time functions in numerical relativity: Marginally bound dust collapse

    D. Eardley and L. Smarr, “Time functions in numerical relativity: Marginally bound dust collapse”, Phys. Rev. D 19, p. 2239-2259 (1979)

  8. [15]

    Ellis and J

    G. Ellis and J. Wainwright, Dynamical systems in cosmology , Cambridge University Press, Cambridge (1997)

  9. [16]

    Hamiltonian reduction and perturb ations of continuously self-similar (n + 1)-dimensional Einstein vacuum spacetimes

    A. Fischer and V. Moncrief, “Hamiltonian reduction and perturb ations of continuously self-similar (n + 1)-dimensional Einstein vacuum spacetimes”, Class. Quantum Gra v. 19, p. 5557-5589 (2002)

  10. [17]

    H-surfaces in Lorentzian manifolds

    C. Gerhardt, “ H-surfaces in Lorentzian manifolds”, Comm. Math. Phys. 89, p. 523 -553 (1983)

  11. [18]

    On strong cosmic censorship

    J. Isenberg, “On strong cosmic censorship”, in Surveys in diffe rential geometry XX , eds. L. Bieri and S.-T. Yau, International Press, Somerville, p. 17-36 (2015)

  12. [19]

    Asymptotic behavior of the gra vitational field and the nature of singu- larities in Gowdy spacetimes

    J. Isenberg and V. Moncrief, “Asymptotic behavior of the gra vitational field and the nature of singu- larities in Gowdy spacetimes”, Adv. Phys. 199, p. 84-122 (1990)

  13. [20]

    Notes on Perelman’s papers

    B. Kleiner and J. Lott, “Notes on Perelman’s papers”, Geom. To p. 12, p. 2587-2855 (2008)

  14. [21]

    Weakly regular T 2-symmetric spacetimes. The global geometry of future Cauchy developments

    P. LeFloch and J. Smulevici, “Weakly regular T 2-symmetric spacetimes. The global geometry of future Cauchy developments”, J. Eur. Math. Soc. 17, 12291292 (2015) ON THE INITIAL GEOMETRY OF A V ACUUM COSMOLOGICAL SPACETIME 2 9

  15. [22]

    Ancient dynamics in Bianchi models: Approach to periodic cycles

    S. Liebscher, J. H¨ arterich, K. Webster and M. Georgi, “Ancient dynamics in Bianchi models: Approach to periodic cycles”, Comm. Math. Phys. 305, p. 59-83 (2011)

  16. [23]

    Dimensional reduction and the long-time behavior of R icci flow

    J. Lott, “Dimensional reduction and the long-time behavior of R icci flow”, Comm. Math. Helv. 85, p. 485-534 (2010)

  17. [25]

    Maximal hypersurfaces and foliation s of mean curvature in general rela- tivity

    J. Marsden and F. Tipler, “Maximal hypersurfaces and foliation s of mean curvature in general rela- tivity”, Phys. Rep. 66, p. 109-139 (1980)

  18. [26]

    Manufacture of Gowdy spacetimes with spikes

    A. Rendall and M. Weaver, “Manufacture of Gowdy spacetimes with spikes”, Class. Quantum Grav. 18, p. 2959-2975 (2001)

  19. [27]

    The Bianchi IX attractor

    H. Ringstr¨ om, “The Bianchi IX attractor”, Annales Henri Po incar´ e 2, p. 405-500 (2001)

  20. [28]

    Existence of an asymptotic velocity and implicat ions for the asymptotic behaviour in the direction of the singularity in T 3-Gowdy

    H. Ringstr¨ om, “Existence of an asymptotic velocity and implicat ions for the asymptotic behaviour in the direction of the singularity in T 3-Gowdy”, Commun. Pure Appl. Math. 59, p. 977-1041 (2006)

  21. [29]

    Cosmic censorship for Gowdy spacetimes

    H. Ringstr¨ om, “Cosmic censorship for Gowdy spacetimes”, Liv ing Reviews in Relativity 13:2, p. 1-59 (2010)

  22. [30]

    On the structure of manifolds with po sitive scalar curvature

    R. Schoen and S.-T. Yau, “On the structure of manifolds with po sitive scalar curvature”, Manuscripta Math. 28, p. 159 -183 (1979) Department of Mathematics, University of California, Berk eley, Berkeley, CA 94720- 3840, USA E-mail address : lott@berkeley.edu

Pith tools

Reviewed August 14, 2026 · model on record in the stance chip above.