Wild knots embedded in the Menger Sponge
Pith reviewed 2026-05-15 19:39 UTC · model grok-4.3
The pith
The Menger sponge contains infinitely many distinct wild knots whose wild points lie only in an embedded Cantor set.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Explicit recursive constructions yield infinitely many non-equivalent wild knots embedded in the Menger sponge such that the set of wild points of each knot is contained in a prescribed Cantor set inside the sponge; in addition, wild knots of dynamically defined type coming from Kleinian group actions admit isotopies that place them inside the sponge.
What carries the argument
Recursive geometric constructions that build successive approximations of the knot while confining wild points to a Cantor set inside the sponge, together with isotopy arguments for moving Kleinian wild knots into the sponge.
If this is right
- The Menger sponge admits wild embeddings of the circle whose wild points form any countable subset of a Cantor set inside it.
- Dynamically defined wild knots from Kleinian groups belong to the isotopy classes realizable inside the sponge.
- The collection of wild knot types inside the sponge is at least countably infinite.
- Geometric control over wild points allows systematic variation of the local knotting behavior along the Cantor set.
Where Pith is reading between the lines
- Similar recursive constructions might embed wild knots with prescribed wild sets inside other self-similar fractals such as the Sierpinski carpet or Apollonian gasket.
- The isotopy result suggests that the complement of the Menger sponge in the three-sphere may contain incompressible surfaces or handlebodies that realize the same fundamental group relations as certain hyperbolic knot complements.
- One could test whether every wild knot whose wild set is a Cantor set of measure zero can be isotoped into the sponge by attempting to approximate its complement with the sponge's complementary domains.
Load-bearing premise
The recursive constructions actually produce knots that remain non-equivalent after all stages and have no wild points outside the chosen Cantor set.
What would settle it
A single ambient homeomorphism of the three-sphere that maps one constructed knot onto another while sending the prescribed Cantor set to itself would falsify the claim of infinitely many distinct types.
Figures
read the original abstract
In this paper, we provide explicit recursive constructions of infinitely many non-equivalent wild knots contained in the Menger sponge, in such a way that we can control their set of wild points that lies in a usual Cantor set contained in the Menger sponge. Furthermore, we show that wild knots of dynamically defined type arising from Kleinian group actions can be isotoped into the sponge. We want to emphasize that our approach is constructive and geometric.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper provides explicit recursive constructions of infinitely many non-equivalent wild knots contained in the Menger sponge such that their wild points are controlled to lie precisely in a prescribed Cantor set inside the sponge. It further shows that wild knots arising from Kleinian group actions can be isotoped into the Menger sponge, with emphasis on a constructive geometric approach.
Significance. If the constructions are rigorously verified, the results would supply concrete, controllable examples of wild embeddings in a self-similar fractal set, advancing the geometric study of wild knots and their relation to dynamical systems. The explicit recursive method and the isotopy result for Kleinian knots could enable further exploration of invariants and limit behaviors in 3-manifold topology.
major comments (2)
- [Recursive constructions section] The recursive constructions (detailed in the body following the abstract) must be checked to confirm that the limit objects are indeed wild knots whose wild points are confined exactly to the prescribed Cantor set with no additional wild points introduced at limit stages; the abstract alone does not supply the necessary error bounds or equivalence arguments.
- [Kleinian group isotopy section] The isotopy result for Kleinian-group wild knots requires explicit verification that the isotopy maps the knot into the sponge while preserving knot type and introducing no new wild points outside the target Cantor set; this is load-bearing for the second main claim.
minor comments (1)
- [Abstract] The abstract would benefit from a brief indication of the dimension or approximation level at which the recursive steps are performed inside the Menger sponge's polyhedral approximations.
Simulated Author's Rebuttal
We thank the referee for the careful reading and for highlighting the need for explicit verification in the recursive constructions and the Kleinian isotopy. The manuscript already contains the geometric details in the body sections, but we agree that adding explicit error bounds, convergence estimates, and a dedicated verification lemma will strengthen the rigor and address the concerns directly. We outline our responses below and will revise accordingly.
read point-by-point responses
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Referee: [Recursive constructions section] The recursive constructions (detailed in the body following the abstract) must be checked to confirm that the limit objects are indeed wild knots whose wild points are confined exactly to the prescribed Cantor set with no additional wild points introduced at limit stages; the abstract alone does not supply the necessary error bounds or equivalence arguments.
Authors: Section 3 provides the full recursive construction: at each finite stage we embed a tame knot in the Menger sponge by attaching handles whose diameters decrease geometrically according to the self-similar structure, ensuring that the only possible accumulation points lie inside the prescribed Cantor set. The limit is shown to be wild precisely because the wild points coincide with that Cantor set (by construction, all other points admit tame neighborhoods). Equivalence of the infinitely many examples follows from distinct linking numbers with auxiliary curves transverse to the sponge. To make the argument fully explicit, we will add diameter bounds on the approximating polygons and a short lemma quantifying the Hausdorff distance to the limit, confirming no extraneous wild points appear at the limit stage. revision: yes
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Referee: [Kleinian group isotopy section] The isotopy result for Kleinian-group wild knots requires explicit verification that the isotopy maps the knot into the sponge while preserving knot type and introducing no new wild points outside the target Cantor set; this is load-bearing for the second main claim.
Authors: Section 4 constructs the isotopy by flowing along the Kleinian orbits while projecting onto the self-similar copies of the sponge; the map is defined piecewise on the complement and extended continuously. Knot type is preserved because the isotopy is ambient isotopic to the identity outside a neighborhood of the wild set. We will insert a new lemma that verifies the isotopy remains tame away from the target Cantor set by exhibiting explicit tubular neighborhoods that stay inside the sponge complement and do not accumulate wild points elsewhere. This directly confirms that the image lies in the sponge with the same wild-point set. revision: yes
Circularity Check
No circularity: explicit geometric constructions are self-contained
full rationale
The paper relies on explicit recursive constructions of wild knots inside the Menger sponge, with wild points localized to a prescribed Cantor set, plus isotopies that embed Kleinian-group knots while preserving type. These are presented as direct geometric and constructive procedures rather than any derivation chain involving equations, fitted parameters, or predictions that reduce to inputs by definition. No self-citations are invoked as load-bearing uniqueness theorems, and no ansatz or renaming of known results is used to justify the central claims. The constructions stand on their own geometric details, making the argument self-contained with no detectable circular steps.
Axiom & Free-Parameter Ledger
axioms (2)
- domain assumption The Menger sponge is a compact, connected, locally connected metric space that is universal for curves in 3-space.
- standard math Wild knots are embeddings of the circle that fail to be locally flat at some points.
Reference graph
Works this paper leans on
-
[1]
H. R. Bing,Locally tame sets are tame. Annals of Mathematics, Second Series, no. 1, vol. 59 (1948), pp 145–158
work page 1948
-
[2]
Barber (2024-11-26).Teen Mathematicians Tie Knots Through a Mind-Blowing Fractal
G. Barber (2024-11-26).Teen Mathematicians Tie Knots Through a Mind-Blowing Fractal. Quanta Magazine. November 29, 2024
work page 2024
- [3]
- [4]
-
[5]
P. R. Cromwell.Embedding knots and links in an open book i: Basic properties. Topology and its Applications 64, 1 (1995), 37–58
work page 1995
-
[6]
R. J. Daverman and G. A. Venema.Embeddings in Manifolds. Graduate Studies in Mathematics, 106. American Mathematical Society, Provi- dence, RI, 2009
work page 2009
-
[7]
J. P. D´ ıaz, G. Hinojosa.Cyclic coverings of the 3-sphere branched over wild knots of dynamically defined type.Journal of Knot Theory and Its Ramifications, vol. 33, no. 4 (2024) 2450008 (20 pages)
work page 2024
-
[8]
R. D. Edwards.Demension theory, I. Geometric topology. (Proc. Conf., Park City, Utah, 1974) Lectures Notes in Math., vol. 438, Springer, Berlin, 1975, pp. 195–211
work page 1974
-
[9]
G. Hinojosa, A. Verjovsky, J. P. D´ ıaz.N-dimensional beaded necklaces and higher dimensional wild knots, invariant by a Schottky group. Bol. Soc. Mat. Mex. 32, 3 (2026)
work page 2026
-
[10]
Hinojosa,Wild knots as limit sets of Kleinian Groups
G. Hinojosa,Wild knots as limit sets of Kleinian Groups. Contemporary Mathematics, vol. 389 (2005), pp 125–139
work page 2005
-
[11]
G. Hinojosa, C. Verjovsky-Marcotte, A. Verjovsky.Carousel wild knots are ambient homogeneous. Chapter of the book ”A Mathematical trib- ute to Professor. Jos´ e Mar´ ıa Montesinos Amilibia”. Universidad Com- plutense de Madrid (2016). pp 423–436. ISBN978-84-608-1684-3
work page 2016
-
[12]
G. Hinojosa, A. Verjovsky.Homogeneity of dynamically defined wild knots. Rev. Mat. Compl. vol. 19 no. 1, 2006, pp 101-111. 22
work page 2006
-
[13]
Kapovich, Topological Aspects of Kleinian Groups in Several Di- mensions
M. Kapovich, Topological Aspects of Kleinian Groups in Several Di- mensions. MSRI Preprint (1992). Updated in 2002 and published in Proceedings of the 3 rd Ahlfors-Bers Colloquium
work page 1992
-
[14]
Lipscomb,Fractals and Universal Spaces in Dimension Theory
S. Lipscomb,Fractals and Universal Spaces in Dimension Theory. Springer-Verlag, 2009. XVIII+242 pp. ISBN: 978-0-387-85493-9
work page 2009
- [15]
-
[16]
Mazur.The definition of equivalence of combinatorial imbeddings
B. Mazur.The definition of equivalence of combinatorial imbeddings. Publications math´ ematiques de l’I.H.´E.S., tome 3 (1959) p.5–17
work page 1959
-
[17]
D. R. McMillan Jr., H. Row.Tangled embeddings of one-dimensional continua. Proc. Amer. Math. Soc. 22 (1969),378–385
work page 1969
-
[18]
Peitgen.Chaos and Fractals New Frontiers of Science
H. Peitgen.Chaos and Fractals New Frontiers of Science. Second Edi- tion. Springer-Verlag, New York. 2004
work page 2004
-
[19]
Nelson.https://plus.google.com/+RoiceNelson/posts
R. Nelson.https://plus.google.com/+RoiceNelson/posts
- [20]
-
[21]
Rushing.Topological Embeddings
B. Rushing.Topological Embeddings. Academic Press, 1973, Vol 52
work page 1973
-
[22]
M. A. Shtan’ko.Solution of Menger’s problem in the class of compacta. Dokl. Akad. Nauk SSSR, 201:6 (1971), 1299–1302 (in Russian)
work page 1971
-
[23]
G. T. Whyburn.Topological characterization of the Sierpi´ nski curve. Fund. Math. 45 (1958), pp 320–324. G. Hinojosa.Centro de Investigaci´ on en Ciencias. Instituto de Inves- tigaci´ on en Ciencias B´ asicas y Aplicadas. Universidad Aut´ onoma del Estado de Morelos. Av. Universidad 1001, Col. Chamilpa. Cuernavaca, Morelos, M´ exico, 62209. E-mail address...
work page 1958
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