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Visual metrics on boundaries of hyperbolic spaces

T0 review · 2 major / 6 minor · reviewed 2026-08-07 · deepseek-v4-flash

Pith's one-line read This expository paper builds visual metrics and round trees to show that hyperbolic boundaries, with their quasisymmetric and conformal-dimension structure, faithfully encode quasi-isometry type.

desk verdict Useful expository survey on visual metrics and round trees, but Corollary 5.10 overstates the allowable visual metric parameter range; the construction only supports a ≤ 2^{1/δ}, not a ≤ e^{2/δ}. read the letter →

arxiv 2506.10108 v1 pith:A67NQ6YU submitted 2025-06-11 math.GT math.GR

classification math.GTmath.GR MSC 20F6730L10
keywords visualmetricshyperbolicgroupsquasisymmetryconformaldimensionGromovboundaryroundtreesHausdorffgeometricgrouptheory
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 expository paper builds, in one place and from elementary ingredients, the theory of visual metrics on boundaries of hyperbolic metric spaces and the round-tree technique for bounding conformal dimension. The two load-bearing results it presents are that two hyperbolic spaces admitting geometric group actions are quasi-isometric exactly when their boundaries, equipped with visual metrics, are quasisymmetric, and that a combinatorial round tree with vertical branching $V$ and horizontal branching $H$ quasi-isometrically embedded in a hyperbolic polygonal complex forces the conformal dimension of the boundary to be at least $1+\log V/\log H$. The article's contribution is pedagogical: it supplies proofs, examples, and figures for statements that are often quoted, so that a reader new to the area can see why visual metrics exist, why their quasisymmetry type is well defined, and how round trees produce the Cantor-set-times-interval curve families used in lower-bound arguments.

What carries the argument

The construction of visual metrics from quasimetrics is one main machine: the Gromov product $(\eta,\eta')_p$ measures how long rays to boundary points fellow-travel, the function $a^{-(\eta,\eta')_p}$ is only a quasimetric with constant $a^\delta$, and one rescales it by a snowflake exponent and applies the chain construction to obtain a metric comparable to the separation function. The other main machine is Gromov's round tree, a negatively curved 2-complex built by gluing sectors of the hyperbolic plane along initial segments so that its boundary is homeomorphic to the product of a Cantor set and an interval; Mackay's combinatorial version packages this as branching parameters $V$ and $H$ in polygonal complexes. The link between the two is that a round tree embedded in a hyperbolic space $X$ provides a curve family in $\partial X$ whose measure obeys the ball-intersection estimate needed for the Hölder-inequality proof that $\operatorname{Confdim}(\partial X) \ge 1 + \log V/\log H$.

What would settle it

Take a $(\delta)$-hyperbolic space and a visual parameter $a$ with $a^\delta>2$, form $\rho(\eta,\eta')=a^{-(\eta,\eta')_p}$, apply the snowflake-chain construction of Section 5.1, and check whether two distinct boundary points receive distance zero; any such example would show the stated range in Corollary 5.10 fails as written.

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Extended reading notes

Core claim

On its own terms, the paper claims that the analytic structure of the boundary of a hyperbolic space is a faithful quasi-isometry invariant, and that the round tree is the right tool for turning combinatorial branching data into quantitative lower bounds on conformal dimension. Concretely, the separation function $\rho(\eta,\eta')=a^{-(\eta,\eta')_p}$ on $\partial X$ is an $a^\delta$-quasimetric, and snowflaking followed by the chain construction converts it into a genuine visual metric; in a CAT($-1$) space the same function with $a=e$ is already a metric. The paper then presents the theorem, due to Paulin and to Buyalo–Schroeder, that quasi-isometries between hyperbolic spaces are exactly the maps inducing quasisymmetries between their visual-metric boundaries, and Mackay's theorem that a quasi-isometrically embedded combinatorial round tree with branching parameters $V$ and $H$ implies $\operatorname{Confdim}(\partial X) \ge 1 + \log V/\log H$. The exposition is aimed at making these statements and their proof strategies available without requiring a long chain of original references.

Load-bearing premise

The visual metric existence theorem rests on the assumption that the quasimetric constant $a^\delta$ is at most 2, because the chain construction is only proved to yield a metric in that range; the text states the broader range $a \le e^{2/\delta}$ without giving an argument for $a^\delta>2$.

Editorial extensions

If this is right

  • The quasisymmetry type of the visual-metric boundary is well defined, so any quasisymmetry invariant, in particular conformal dimension, is a quasi-isometry invariant of hyperbolic groups.
  • A quasi-isometry between hyperbolic spaces extends to a quasisymmetry of boundaries, so rigidity statements such as Mostow-type theorems can be approached by promoting boundary quasisymmetries to conformal maps.
  • If a hyperbolic polygonal complex admits a quasi-isometrically embedded combinatorial round tree with vertical branching $V$ and horizontal branching $H$, its boundary has conformal dimension at least $1+\log V/\log H$; in particular such a boundary cannot be quasisymmetrically equivalent to one of lower dimension.
  • Mackay's application shows that every one-ended hyperbolic group whose boundary has no local cut points has conformal dimension strictly greater than one, ruling out quasi-isometry with free groups in that class.
  • For random groups at density below $1/8$, the round-tree lower bound grows with the relator length, giving infinitely many quasi-isometry classes among generic groups.

Reading between the lines

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

  • The paper's elementary treatment suggests that the sharp range for visual metric parameters should be $a^\delta \le 2$; if the stated range $a \le e^{2/\delta}$ is literal, the proof in the text does not cover the upper part, so a corrected argument or a corrected range is needed.
  • The same Hölder-measure strategy that proves $\operatorname{Confdim}(C\times[0,1]) = 1+\dim_H(C)$ could be tested on other uniformly disconnected fractals: if a fractal's conformal dimension is zero, its product with an interval may often attain the sum of dimensions, giving a general stabilization principle.
  • The combinatorial round-tree lower bound could be adapted to Bowditch boundaries of relatively hyperbolic pairs, as the paper's survey of Coxeter-group work indicates; testing it on groups with Pontryagin sphere boundary is a natural next step.
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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 / 6 minor

Summary. This expository paper surveys visual metrics on boundaries of hyperbolic metric spaces, covering the construction of visual metrics from quasimetrics, quasisymmetries and their invariants, Hausdorff and conformal dimension, and Gromov's round trees as a tool for lower bounds on conformal dimension. It is based on a minicourse and aims to give a unified, elementary treatment with many examples and proofs, including a discussion of recent applications to Bourdon buildings, random groups, and relatively hyperbolic Coxeter groups.

Significance. If the technical issues are fixed, this survey would be a valuable and accessible introduction to the subject. Its strengths include a clear organization, a large number of worked examples, explicit proofs for foundational results (e.g., the chain construction, snowflaking, and the Hausdorff dimension of tree boundaries), and a useful compilation of the round tree technique and its applications. It also fills a niche by providing proofs that are not always easily available in the literature. The paper does not claim new results, but it serves as a cohesive reference. However, the error in Corollary 5.10 concerns the central construction advertised in the abstract and must be corrected before the survey can be relied upon.

major comments (2)
  1. [§5.1, Corollary 5.10] The stated parameter range a ∈ (1, e^{2/δ}] is not justified by the cited proof. Lemma 5.4 shows that ρ is an a^δ-quasimetric, and Proposition 5.6 applies only when the quasimetric constant is at most 2, i.e., when a^δ ≤ 2, which is equivalent to a ≤ 2^{1/δ}. The alternative route through Proposition 5.9 via snowflaking yields a metric bilipschitz to ρ^ε, which is a visual metric with parameter a^ε, not a. Therefore the proof as written establishes at most the range (1, 2^{1/δ}], and the stated range (1, e^{2/δ}] is false without an additional argument. This is a load-bearing statement because the construction of visual metrics is a central theme of the paper. Additionally, the inequality in the corollary refers to d_ϵ, but the metric is called d_a; this notation should be fixed.
  2. [§6.2, Lemma 6.7(1)] As written, this lemma claims that visual metrics d_a and d_{a'} with different parameters a and a' are bilipschitz equivalent. This is false in general; for example, on the boundary of a 4-regular tree, d_a(η, η') = a^{-k} and d_{a'}(η, η') = (a')^{-k} for points at distance k in the tree, and the ratio (a'/a)^k is unbounded as k varies. The proof only establishes bilipschitz equivalence for the same parameter a with different basepoints, since it uses the inequality |(η, η')_p − (η, η')_{p'}| ≤ d(p, p'). The statement should be corrected to say 'Let d_a and d'_a be visual metrics on ∂X with the same parameter a and basepoints p and p'.' Without this correction, a reader may draw an incorrect conclusion about the invariance of the quasisymmetry type.
minor comments (6)
  1. [§3.2, Definition 3.7] In the second paragraph, 'N(x) the the collection' contains a duplicated article; it should read 'N(x) the collection'.
  2. [§5.2, Theorem 5.11] The displayed map is written as ρ : ∂X → ∂X, but it should be ρ : ∂X × ∂X → [0, ∞) to match the definition of ρ(η, η').
  3. [§5.1, proof of Proposition 5.6] The phrase 'a contraction' at the end of the proof should be 'a contradiction'.
  4. [§7.2, Example 7.16] The definition of covering dimension is missing the logarithm: it should be dim_covering(Z,d) := lim_{ε→0} log N(ε)/log(1/ε). The subsequent computation correctly uses the logarithmic version, so this is a typographical error.
  5. [§8.1, Proposition 8.5] The text says 'a probability measure μ on E' in the setup but then uses ν in condition (2); the measure on the curve family should be denoted consistently, probably ν, to avoid confusion with the measure μ on Z.
  6. [§8.4, Theorem 8.15] The expression 'log(2m − 1)dℓ' is ambiguous and should be written as 'dℓ log(2m − 1)' or 'log((2m−1)^{dℓ})' to clearly indicate that the logarithm multiplies the length ℓ.

Circularity Check

0 steps flagged · score 1.0 of 10

Survey is externally benchmarked; the only flagged issue (Corollary 5.10's visual-parameter range) is a localized correctness concern, not a circular derivation.

full rationale

This is an expository survey rather than a new derivation, and its load-bearing assertions are imported from independent external sources: Theorem 1.1 and Theorem 6.12 cite Paulin and Buyalo-Schroeder for the quasi-isometry/quasisymmetry correspondence, and Theorem 8.10 cites Mackay for the combinatorial round tree conformal-dimension bound. The visual metric construction in Section 5.1 is carried out explicitly from Lemmas 5.4 and Propositions 5.6 and 5.9, and it does not rely on any fitted parameter or on a self-referential prediction. The only potentially problematic part of the paper is Section 8.5, where results from the author's own joint works [FGLS] and [CDSS] are surveyed; these are clearly attributed and are presented as applications rather than used to justify the paper's foundational constructions, so they are not load-bearing self-citations in the sense of circularity. I also flag the reader's correctness concern: Corollary 5.10 states 'For all a ∈ (1, e^{2/δ}], there exists a visual metric d_a on ∂X with visual metric parameter a,' but the proof cited uses Proposition 5.6, which requires the quasimetric constant K ≤ 2; since Lemma 5.4 gives K = a^δ, the construction as written proves the range a ≤ 2^{1/δ}, and snowflaking would change the visual parameter rather than extend the range to e^{2/δ}. This appears to be a typo or a missing argument in the exposition, not a circular step, because the construction does not presuppose the conclusion it claims to prove.

Assumptions & free parameters 0 free parameters · 5 assumptions · 0 invented entities

The paper introduces no fitted parameters and no new entities. It is a survey, so its content rests on a set of field-standard theorems quoted from the literature. The most consequential quoted inputs are the quasi-isometry/quasisymmetry correspondence, Coornaert's Hausdorff dimension formula, and Mackay's round tree bound, plus an internal lemma (Lemma 4.5) whose proof is only sketched.

assumptions (5)
  • domain assumption Quasi-isometry of proper geodesic hyperbolic spaces is equivalent to quasisymmetry of their visual metric boundaries (Theorem 6.12, credited to Paulin and Buyalo-Schroeder).
    This is the central bridge making conformal dimension a quasi-isometry invariant; it is quoted, not proved in the article.
  • domain assumption Coornaert's formula: for a hyperbolic group acting geometrically on X, Hausdim(∂X,d_a)=h/log a (Theorem 7.19).
    Used to compute Hausdorff dimensions and to identify conformal dimension with the infimum over visual parameters; the proof is not included.
  • domain assumption Mackay's combinatorial round tree theorem: a quasi-isometrically embedded round tree with vertical branching V and horizontal branching at most H gives Confdim(∂X)≥1+logV/logH (Theorem 8.10).
    The applications in Section 8 depend on this theorem, which is stated but not proved.
  • domain assumption The boundary of a hyperbolic group is well-defined up to homeomorphism and quasi-isometries induce boundary homeomorphisms (Theorem 3.10, Bridson-Haefliger).
    Foundational for everything that follows; quoted as standard.
  • domain assumption For any two boundary points there exist sequences realizing the extended Gromov product as a limit (Lemma 4.5, proved by a sketched diagonal argument).
    This lemma underpins the extension of the δ-inequality to the boundary and hence the quasimetric property of ρ; no full proof is supplied.

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Pith. "Pith review of Visual metrics on boundaries of hyperbolic spaces." pith.science (2026). https://pith.science/paper/A67NQ6YU

@misc{pith2026250610108,
  author       = {Pith},
  title        = {Pith review of: Visual metrics on boundaries of hyperbolic spaces},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/A67NQ6YU}},
  note         = {Machine review of arXiv:2506.10108}
}
read the original abstract

This is an expository article on visual metrics on boundaries of hyperbolic metric spaces. We discuss the construction of visual metrics, quasisymmetries and their invariants, Hausdorff and conformal dimension, and constructions and applications of Gromov's round trees. There is a focus on providing examples throughout. These notes are based on the material of a minicourse given by the author at the 2024 Riverside Workshop in Geometric Group Theory.

Figures

Figures reproduced from arXiv: 2506.10108 by the authors.

Figure 1
Figure 1. The Gromov product in a metric tree. The above example generalizes to a δ-hyperbolic space: the Gromov product between x and y with respect to a point p captures, up to a few δ, how far p is from the geodesic between x and y. Lemma 2.9. [BH99, Page 410; Proposition III.H.1.17] Let X be a δ-hyperbolic geodesic metric space. Let p, x, y ∈ X, and let [x, y] denote a geodesic segment from x to y. Then, for all x, y, p ∈… view at source ↗
Figure 2
Figure 2. Checking the δ-inequality in a tree. Remark 2.12. The (δ)-hyperbolicity definition also has a natural accompanying picture that indicates a notion of thinness. The definition of Gromov product implies that a metric space X is (δ)-hyperbolic if and only if for all p, x, y, z ∈ X, d(x, p) + d(y, z) ≤ max d(x, y) + d(z, p), d(x, z) + d(y, p) [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗
Figure 3
Figure 3. The 4-point hyperbolicity condition [PITH_FULL_IMAGE:figures/full_fig_p007_3.png] view at source ↗
Figures from the paper (18 more)
Figure 4
Figure 4. Figure 4: A metric space with visual boundary consisting of two points. 3.2. Topology on the boundary. The boundary of X admits a topology that compactifies the metric space X. We first specify notation for the union of X and its boundary. Definition 3.5. Let X be a metric space…
Figure 5
Figure 5. Figure 5: A neighborhood in ∂X of the boundary point represented by the ray c0 consists of equivalence classes of rays with a representative passing through the shaded ball. (1) If N ∈ N (x), then x ∈ N. (2) If N ⊂ N′ and N ∈ N (x), then N′ ∈ N (x). (3) If N, N′ ∈ N (x), then N …
Figure 6
Figure 6. Figure 6: An example illustrating that neighborhoods in the boundary need not be open. The hyperbolic space X is formed by cutting the hyperbolic plane into two pieces and gluing them together along intervals of length one evenly spaced along the boundary geodesics. The neighbor…
Figure 7
Figure 7. Figure 7: Sequences converging to the same point on the boundary. Hence, both sequences {xi} and {x ′ i } converge to infinity, and the sequences are equivalent. The δ-inequality implies that being equivalent in the sense of Definition 3.12 is an equivalence relation on the set …
Figure 8
Figure 8. Figure 8: An example of Bridson–Haefliger that motivates the definition of the exten￾sion of the Gromov product to the boundary. Example 4.3 ([BH99], Example III.H.3.16). The following example of Bridson–Haefliger illus￾trates why both an infimum and a lim inf are needed to make…
Figure 9
Figure 9. Figure 9: The function αp corresponds to half the chordal metric on the circle. For the points illustrated on the unit circle above, sin ∠ypy′ 2 is the length of the highlighted blue segment. Sketch of the proof of Theorem 5.11. The proof of the theorem follows from three claims…
Figure 10
Figure 10. Figure 10: A portion of the Cayley graph for Z/10Z∗Z/10Z that illustrates the failure of the triangle inequality in a potential metric on the boundary. Then (η, η′ )p = 0, (η, η′′)p = 2, (η ′ , η′′)p = 2. So, ρ(η, η′ ) = 1, ρ(η, η′′) = e −2 , and ρ(η ′ , η′′) = e −2 . Hence, the…
Figure 11
Figure 11. Figure 11: An example of a circle boundary of a hyperbolic group so that the bound￾ary is not a geodesic metric space when equipped with the visual metric. Illustrated are geodesic rays and geodesic lines in a CAT(−1) polygonal complex X described in Example 5.18 with boundary ∂…
Figure 12
Figure 12. Figure 12: Extensions of isometries of the tree to the boundary distort the distance between pairs of these rays in the visual metric, but they preserve the ratio of distances between the rays in this triple. arbitrarily bad: de(a k η, ak η ′ ) = e −(a kη,akη ′ )p = e −(k+1) . H…
Figure 13
Figure 13. Figure 13: Distortion of annuli under a quasisymmetry. Notation 6.3. Let Z be a metric space. Let Br(z) denote the ball of radius r about z ∈ Z. For K ≥ 0, let KBr(z) := BKr(z). For example, let r > 0 and t > 1 and consider the annulus A = Brt(x) \ Br(x). Suppose f : Z → Z ′ is …
Figure 14
Figure 14. Figure 14: The logarithm of the cross ratio, log[x, y, z, w], corresponds in a tree to the distance in the tree between the geodesics with endpoints x, w and y, z on the boundary. In a δ-hyperbolic space, this captures the same distance, up to a few δ. Suppose f : X → X′ is a qu…
Figure 15
Figure 15. Figure 15: The boundary of a hyperbolic group is a doubling metric space. On the left, the ball of radius 2 −k about z ∈ ∂T corresponds to all rays in the tree passing through the vertex v. This ball is covered by the three balls of radius 1 2 2 −k corresponding to the three red…
Figure 15
Figure 15. Figure 15: Since the Cayley graph of a hyperbolic group is uniformly locally finite, one concludes [PITH_FULL_IMAGE:figures/full_fig_p031_15.png]
Figure 16
Figure 16. Figure 16: Covers of the boundary of the tree corresponding to vertices on spheres about p. 7.2. Hausdorff dimension of boundaries. Coornaert [Coo93] computed the Hausdorff dimen￾sion of the boundary of a hyperbolic group equipped with a visual metric. This result, which is stat…
Figure 17
Figure 17. Figure 17: A stabilization occurs with respect to conformal dimension upon taking the product with an interval. While the conformal dimension of the two-thirds Cantor set is zero, the conformal dimension of the product of the Cantor set and the interval is achieved by the Hausdo…
Figure 18
Figure 18. Figure 18: Gromov’s round trees. We now state two generalizations of Theorem 8.1. Their proofs are modeled on an argument due to Pansu [Pan89a, Proposition 2.9], [Pan89b, Lemma 6.3] and follow the same reasoning as in the theorem above. The curve family and its measure allows on…
Figure 19
Figure 19. Figure 19: A portion of a round tree obtained by gluing sectors of the hyperbolic plane (viewed in the disk model) along initial subcomplexes. The boundary of the limiting object is homeomorphic to the product of the Cantor set and an interval. Example 8.6. [Gro93, Page 136] Gro…
Figure 20
Figure 20. Figure 20: Building a round tree in a Bourdon building I5,3. The complex is extended along strips at each vertex; this construction at v is possible as the link of a vertex v contains many 4-cycles that intersect only in an edge. proved that the conformal dimension values over a…

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  1. Conformal dimension bounds, Pontryagin sphere boundaries, and algebraic fibering of right-angled Coxeter groups

    math.GR 2025-10 conditional novelty 7.0 of 10

    (n,m)-branching graphs give right-angled Coxeter groups with boundary conformal dimension at least 1 + log n/log(3m-7), yielding infinitely many quasi-isometry classes with Pontryagin sphere boundary and with virtual ...

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Works this paper leans on

16 extracted references · 13 canonical work pages · cited by 1 Pith paper

  1. [1980]

    Quasi-Möbius maps

    [V¨85] Jussi Väisälä. Quasi-Möbius maps. J. Analyse Math., 44:218–234, 1984/85. [Wis96] Daniel T. Wise. Non-positively curved squared complexes: Aperiodic tilings and non-residually finite groups. ProQuest LLC, Ann Arbor, MI,

  2. [1984]

    [Can91] James W. Cannon. The theory of negatively curved spaces and groups. In Ergodic theory, symbolic dynamics, and hyperbolic spaces (Trieste, 1989), Oxford Sci. Publ., pages 315–369. Oxford Univ. Press, New York,

  3. [1987]

    [Gro93] M. Gromov. Asymptotic invariants of infinite groups. InGeometric group theory, Vol. 2 (Sussex, 1991), volume 182 ofLondon Math. Soc. Lecture Note Ser., pages 1–295. Cambridge Univ. Press, Cambridge,

  4. [1990]

    Conformal dimension bounds for certain Coxeter group Bowditch boundaries

    Mathematical founda- tions and applications. [FGLS] Elizabeth Field, Radhika Gupta, Robert Alonzo Lyman, and Emily Stark. Conformal dimension bounds for certain Coxeter group Bowditch boundaries. arXiv:2504.12404. [Fis03] Hanspeter Fischer. Boundaries of right-angled Coxeter groups with manifold nerves.Topology, 42(2):423– 446,

  5. [1992]

    Boundaries of hyperbolic groups

    [KB02] Ilya Kapovich and Nadia Benakli. Boundaries of hyperbolic groups. In Combinatorial and geometric group theory (New York, 2000/Hoboken, NJ, 2001), volume 296 of Contemp. Math., pages 39–93. Amer. Math. Soc., Providence, RI,

  6. [1993]

    On the conformal gauge of a compact metric space

    [CP13] Matias Carrasco Piaggio. On the conformal gauge of a compact metric space. Ann. Sci. Éc. Norm. Supér. (4), 46(3):495–548 (2013),

  7. [1998]

    [Bou18] Marc Bourdon

    Translated from the French, Reprint of the 1989 English translation. [Bou18] Marc Bourdon. Mostow type rigidity theorems. In Handbook of group actions. Vol. IV, volume 41 of Adv. Lect. Math. (ALM), pages 139–188. Int. Press, Somerville, MA,

  8. [2000]

    Quasi-conformal geometry and hyperbolic geometry

    [BP02] Marc Bourdon and Hervé Pajot. Quasi-conformal geometry and hyperbolic geometry. In Rigidity in dynamics and geometry (Cambridge, 2000), pages 1–17. Springer, Berlin,

Show all 16 references
  1. [2001]

    Christopher Hruska

    [HH] Burns Healy and G. Christopher Hruska. Cusped spaces and quasi-isometries of relatively hyperbolic groups. arXiv:2010.09876. [HHS20] Matthew Haulmark, G. Christopher Hruska, and Bakul Sathaye. Nonhyperbolic Coxeter groups with Menger boundary.Enseign. Math., 65(1-2):207–220,

  2. [2003]

    Round trees and conformal dimension in random groups: low density to high density

    [Fro] Jordan Frost. Round trees and conformal dimension in random groups: low density to high density. arXiv:2204.05165. [Gab92] David Gabai. Convergence groups are Fuchsian groups. Ann. of Math. (2), 136(3):447–510,

  3. [2004]

    [Jak91] W

    [HS] NimaHodaandJacekŚwiątkowski.Treesofgraphsasboundariesofhyperbolicgroups.arXiv:2312.15827. [Jak91] W. Jakobsche. Homogeneous cohomology manifolds which are inverse limits.Fund. Math., 137(2):81–95,

  4. [2006]

    Trees of manifolds and boundaries of systolic groups.Fund

    [Zaw10] Paweł Zawiślak. Trees of manifolds and boundaries of systolic groups.Fund. Math., 207(1):71–99, 2010

  5. [2009]

    Séminaire Bourbaki. Vol. 2007/2008. [Haï18] Peter Haïssinsky. Actions of quasi-Möbius groups. In Handbook of group actions. Vol. IV, volume 41 of Adv. Lect. Math. (ALM), pages 23–94. Int. Press, Somerville, MA,

  6. [2010]

    [Opp] Izhar Oppenheim

    Theory and application. [Opp] Izhar Oppenheim. Banach zuk’s criterion for partite complexes with application to random groups. arXiv:2112.02929. [Pan89a] Pierre Pansu. Dimension conforme et sphère à l’infini des variétés à courbure négative.Ann. Acad. Sci. Fenn. Ser. A I Math....

  7. [2016]

    [Mac25] John M. Mackay. Conformal dimension and hyperbolic groups. volume 63 ofPanor. Synthèses, pages 145–170. Soc. Math. France, Paris, [2025]©2025. [Mos73] G. D. Mostow. Strong rigidity of locally symmetric spaces. Annals of Mathematics Studies, No

  8. [2018]

    [DLMR] Sami Douba, Gye-Seon Lee, Ludovic Marquis, and Lorenzo Ruffoni

    With an appendix by Bogdan Nica. [DLMR] Sami Douba, Gye-Seon Lee, Ludovic Marquis, and Lorenzo Ruffoni. Convex cocompact groups in real hyperbolic spaces with limit set a pontryagin sphere. arXiv:2502.09470. [DO07] JanDymaraandDamianOsajda.Boundariesofright-angledhyperbolicbui...

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