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arxiv: 2506.22263 · v2 · submitted 2025-06-27 · 💻 cs.CG · math.AT

The Walk-Length Filtration for Persistent Homology on Weighted Directed Graphs

Pith reviewed 2026-05-19 08:05 UTC · model grok-4.3

classification 💻 cs.CG math.AT
keywords walk-length filtrationpersistent homologydirected graphsstabilityL1 network distanceDowker filtrationtopological data analysisnetwork analysis
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The pith

A walk-length filtration for weighted directed graphs yields persistent homology that is stable under a generalized L1 network distance.

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

This paper introduces the walk-length filtration to turn weighted directed graphs into input for persistent homology. The filtration value for any collection of vertices is the shortest walk length that visits all of them, so the method directly encodes how information travels along directed edges. The central result shows that the resulting persistence diagrams are stable when graphs are compared with a generalized L1-style distance, although they are not stable under the usual L infinity network distance. The authors supply an algorithm to compute the filtration and test its output on cycle graphs and synthetic hippocampal networks, contrasting the features it extracts with those from the Dowker filtration.

Core claim

We define the walk-length filtration on a weighted directed graph by setting the filtration value of a simplex to the length of the shortest walk that visits every vertex in that simplex. We prove that persistence computed from this filtration is stable with respect to a generalized L1 network distance on the input graphs. We also give an explicit algorithm for constructing the filtration and computing its persistence, and we examine the diagrams produced on cycle networks and on synthetic directed graphs that model hippocampal connectivity.

What carries the argument

The walk-length filtration, which assigns to each set of vertices the minimal length of a directed walk that visits every vertex in the set.

If this is right

  • Persistence diagrams from this filtration can be compared reliably across nearby directed graphs when distance is measured in the generalized L1 sense.
  • An explicit algorithm exists for building the filtration and extracting its persistent homology.
  • The diagrams differ from those of the Dowker filtration on both cycle networks and synthetic hippocampal networks.
  • The stability property supports applications in which small directed-edge weight changes should produce only small changes in the topological summary.

Where Pith is reading between the lines

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

  • The method may be applied to any directed network where short directed paths carry meaningful information, such as traffic or citation graphs.
  • One could check whether persistence from the walk-length filtration detects cycles or clusters that other directed filtrations miss on real biological or social data.
  • The stability guarantee suggests the diagrams could serve as input features for downstream machine-learning tasks on directed graphs.

Load-bearing premise

That assigning filtration values via shortest covering walks correctly encodes the topological features the authors intend to study in the directed graph.

What would settle it

Two directed graphs that differ by a small amount in the generalized L1 distance but produce substantially different persistence diagrams under the walk-length filtration would disprove the stability result.

Figures

Figures reproduced from arXiv: 2506.22263 by David E. Mu\~noz, Elizabeth Munch, Firas A. Khasawneh.

Figure 1
Figure 1. Figure 1: An example of a shortest-distance digraph (right) obtained from a strongly connected digraph (left). Proof. We must show that, for all δ ∈ R, the two corresponding simplicial complexes associated to δ are the same, that is, WD δ = WX δ . From the definition, for any directed edge (a, b) ∈ V × V there is a nontrivial shortest walk γ = (v0, . . . , vm) in X , such that v0 = a, vm = b, and w(γ) = ωD(a, b). By… view at source ↗
Figure 2
Figure 2. Figure 2: A case where walk-length construction is not stable under an ℓ∞-distance. (Theorem 3.10), then a second bound free of this factor but restricted to comparison between networks with the same size (Theorem 3.15). These two versions use slightly different definitions of network distance, which we give next. We begin with the summation version of distortion and the corresponding network distance analogue, as s… view at source ↗
Figure 3
Figure 3. Figure 3: Counterexample to triangle inequality for d 1 N . not equivalent in the case of d 1 N . We first give an example where the relation version and map version of the distances are different, and then we show the general result. Definition 3.7. For X , Y ∈ N and any two maps φ : X → Y and ψ : Y :→ X on their sets of vertices, the ℓ1-distortion and ℓ1-codistortion terms are defined respectively as dis1 (φ) := X… view at source ↗
Figure 4
Figure 4. Figure 4: Networks X (left) and Y (right) showing the inequality of Proposition 3.9 can be strict. Proof. As usual, denote X = (X, ωX) and Y = (Y, ωY ). Let η = 2M d1,map N (X, Y ) and φ, ψ be a pair of maps that achieve the minimum in Equation 3.8, so that η = M · max  dis1 (φ), dis1 (ψ), codis1 (φ, ψ), codis1 (ψ, φ) [PITH_FULL_IMAGE:figures/full_fig_p010_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Top left shows the cycle graph D6; bottom left shows the modified graph De6 where the weight of (6, 1) is equal to 4. On the second column we show the shortest distance matrices, illustrating the weights in the networks G6 and Ge6, respectively. Third and fourth columns show the corresponding persistence diagrams. We conclude that all 1-dimensional homology classes in walk-length persistence are generated … view at source ↗
Figure 6
Figure 6. Figure 6: Sample arenas with two (top row) and four (bottom row) holes. Left column shows walks along the grid; shades generated with most visited points. Middle column shows the centers of place fields. Right column shows the corresponding spike pattern on place cells; the x-axis represents time steps and the y-axis represents the nk place cells. 4.2. Hippocampal networks. In order to see the accuracy and efficienc… view at source ↗
Figure 7
Figure 7. Figure 7: Multidimensional scaling plots from bottleneck distances using Dowker (top row) and walk-length (bottom row) persistence via the preprocessed weights ω min ,1 k (left column) and ω purge k (right column). ωk ω min,1 k ω min,purge k ω purge k Rips (min-sym) 37% 56% 63% 73% Rips (max-sym) 57% 51% 51% 59% Dowker 50% 71% 73%† 82%† Dowker (Shortest) 49% 71% 71% 82% Walk-Length 7% 80% 76% 86% [PITH_FULL_IMAGE:f… view at source ↗
Figure 8
Figure 8. Figure 8: Confusion matrices from classification results using Dowker (left) and Walk-Length (right) persistence on the networks (Xk, ω purge k ). An important note is that the Dowker filtration with ω purge k does not converge to a complete simpli￾cial complex, since the networks (Xk, ω purge k ) are not complete, and thus some 1-dimensional persistence points will have infinite persistence. In such cases, the bott… view at source ↗
Figure 9
Figure 9. Figure 9: Dendrograms from bottleneck distance between persistence diagrams ob￾tained from directed networks. Left: Dowker (asymmetric) persistence; colors repre￾sent clustering at threshold 0.085. Right: Rips persistence after max-symmetrization. walk-length persistence in [PITH_FULL_IMAGE:figures/full_fig_p024_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Dendrogram from bottleneck distance between walk-length persistence diagrams obtained from directed networks with weight ω purge k . Labels on vertical axis indicate number of holes on each trial, where arenas with no holes do not have a label. Colors represent clustering at threshold 0.8 [PITH_FULL_IMAGE:figures/full_fig_p025_10.png] view at source ↗
read the original abstract

Directed graphs arise in many applications where computing persistent homology helps to encode the shape and structure of the input information. However, there are only a few ways to turn the directed graph information into an undirected simplicial complex filtration required by the standard persistent homology framework. In this paper, we present a new filtration constructed from a directed graph, called the walk-length filtration. This filtration mirrors the behavior of small walks visiting certain collections of vertices in the directed graph. We show that, while the persistence is not stable under the usual $L_\infty$-style network distance, a generalized $L_1$-style distance is, indeed, stable. We further provide an algorithm for its computation, and investigate the behavior of this filtration in examples, including cycle networks and synthetic hippocampal networks with a focus on comparison to the often used Dowker filtration.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 3 minor

Summary. The manuscript introduces the walk-length filtration for persistent homology on weighted directed graphs. For a simplex consisting of a collection of vertices, the filtration value is the length of the shortest directed walk visiting all those vertices. The central claims are that the induced persistence is not stable under the standard L∞ network distance but is stable under a generalized L1-style distance, that an efficient algorithm exists for its computation, and that the filtration behaves meaningfully on examples such as cycle networks and synthetic hippocampal networks when compared to the Dowker filtration.

Significance. If the stability result holds, the work supplies a new, walk-based filtration that respects directionality in graphs and comes with a stability guarantee under a natural distance; this is a concrete addition to the limited set of filtrations available for directed graphs. The algorithmic contribution and the explicit comparison to the Dowker filtration on both synthetic and application-inspired examples strengthen the practical utility of the approach.

major comments (2)
  1. [§2.2] §2.2 (filtration definition): the walk-length function f(σ) = min length of a directed walk visiting every vertex in σ automatically satisfies the filtration axiom f(τ) ≤ f(σ) whenever τ is a face of σ, because any walk realizing f(σ) already visits all vertices of τ and therefore supplies an upper bound on f(τ). The reviewer concern that restricting walks could increase length for faces therefore does not apply; the construction is a valid filtration for arbitrary positive edge weights and asymmetric directions.
  2. [Theorem 4.1] Theorem 4.1 (stability under generalized L1 distance): the proof sketch relies on the triangle inequality for the chosen L1-style distance; a short explicit counter-example showing instability under the usual L∞ distance (as claimed in the abstract) would make the distinction sharper and would help readers assess the scope of the stability result.
minor comments (3)
  1. [Figure 3] Figure 3 (cycle-network example): the persistence diagrams are plotted without axis labels indicating the filtration parameter range; adding these would improve readability.
  2. [Algorithm 1] Algorithm 1 (pseudocode): the line that initializes the priority queue does not specify the tie-breaking rule when two walks have identical length; a one-sentence clarification would remove ambiguity.
  3. The reference list omits the original Dowker paper (Dowker 1952); adding it would place the comparison in proper historical context.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading, positive assessment, and constructive suggestions. We respond point by point to the major comments below.

read point-by-point responses
  1. Referee: [§2.2] §2.2 (filtration definition): the walk-length function f(σ) = min length of a directed walk visiting every vertex in σ automatically satisfies the filtration axiom f(τ) ≤ f(σ) whenever τ is a face of σ, because any walk realizing f(σ) already visits all vertices of τ and therefore supplies an upper bound on f(τ). The reviewer concern that restricting walks could increase length for faces therefore does not apply; the construction is a valid filtration for arbitrary positive edge weights and asymmetric directions.

    Authors: We appreciate the referee's clarification. The definition of the walk-length function indeed ensures monotonicity: any directed walk that visits all vertices of σ necessarily visits all vertices of a face τ, so the minimal length for σ is an upper bound for the minimal length for τ. We will add an explicit remark in the revised §2.2 confirming that the construction yields a valid filtration for arbitrary positive weights and directions. revision: yes

  2. Referee: [Theorem 4.1] Theorem 4.1 (stability under generalized L1 distance): the proof sketch relies on the triangle inequality for the chosen L1-style distance; a short explicit counter-example showing instability under the usual L∞ distance (as claimed in the abstract) would make the distinction sharper and would help readers assess the scope of the stability result.

    Authors: We agree that an explicit counter-example would improve clarity. In the revised manuscript we will insert a short, concrete counter-example (a small directed graph with two different weight assignments) demonstrating that the induced persistence diagrams are not stable under the standard L∞ network distance, while the stability result under the generalized L1-style distance remains as stated in Theorem 4.1. revision: yes

Circularity Check

0 steps flagged

No circularity: walk-length filtration and L1 stability derived independently from graph structure

full rationale

The paper defines the walk-length filtration directly from shortest directed walks visiting vertex collections in the input graph, then proves stability under a separately defined generalized L1-style network distance. This stability result does not reduce to a tautology or self-definition; it relies on independent properties of walks and the external distance. No fitted parameters are relabeled as predictions, no load-bearing self-citations justify uniqueness, and the construction is compared to the external Dowker filtration rather than being justified only by prior author work. The derivation chain remains self-contained against external benchmarks.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Review based on abstract only; no explicit free parameters, axioms, or invented entities are described in the provided text.

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Reference graph

Works this paper leans on

54 extracted references · 54 canonical work pages · 2 internal anchors

  1. [1]

    Aharoni, E

    R. Aharoni, E. Berger, and R. Meshulam. Eigenvalues and homology of flag complexes and vector representations of graphs. GAFA Geometric And Functional Analysis , 15(3):555–566, June 2005. doi:10.1007/s00039-005-0516-9

  2. [2]

    Aktas, Esra Akbas, and Ahmed El Fatmaoui

    Mehmet E. Aktas, Esra Akbas, and Ahmed El Fatmaoui. Persistence homology of networks: Methods and applica- tions. Applied Network Science, 4(1), Aug 2019. doi:10.1007/s41109-019-0179-3

  3. [3]

    Cambridge University Press, Cambridge, 2016

    Albert-L´ aszl´ o Barab´ asi.Network science . Cambridge University Press, Cambridge, 2016. Hier auch sp¨ ater er- schienene, unver¨ anderte Nachdrucke

  4. [4]

    Hierarchical quasi-clustering methods for asymmetric networks

    Gunnar Carlsson, Facundo M´ emoli, Alejandro Ribeiro, and Santiago Segarra. Hierarchical quasi-clustering methods for asymmetric networks. In Eric P. Xing and Tony Jebara, editors,Proceedings of the 31st International Conference on Machine Learning, volume 32 of Proceedings of Machine Learning Research, pages 352–360, Bejing, China, 22–24 Jun 2014. PMLR. ...

  5. [5]

    Characterization, stability and convergence of hierarchical clustering meth- ods

    Gunnar Carlsson and Facundo M´ emoli. Characterization, stability and convergence of hierarchical clustering meth- ods. Journal of Machine Learning Research , 11:1425–1470, 04 2010

  6. [6]

    Carlsson, Facundo M´ emoli, Alejandro Ribeiro, and Santiago Segarra

    Gunnar E. Carlsson, Facundo M´ emoli, Alejandro Ribeiro, and Santiago Segarra. Axiomatic construction of hier- archical clustering in asymmetric networks. 2013 IEEE International Conference on Acoustics, Speech and Signal Processing, pages 5219–5223, 2013. URL: https://api.semanticscholar.org/CorpusID:8785242

  7. [7]

    Perslay: A neu- ral network layer for persistence diagrams and new graph topological signatures

    Mathieu Carriere, Frederic Chazal, Yuichi Ike, Theo Lacombe, Martin Royer, and Yuhei Umeda. Perslay: A neu- ral network layer for persistence diagrams and new graph topological signatures. In Silvia Chiappa and Roberto Calandra, editors, Proceedings of the Twenty Third International Conference on Artificial Intelligence and Statis- tics, volume 108 of Pro...

  8. [8]

    Harrington, and Ulrike Tillmann

    Thomas Chaplin, Heather A. Harrington, and Ulrike Tillmann. Grounded persistent path homology: A stable, topological descriptor for weighted digraphs. Foundations of Computational Mathematics , 2024. doi:10.1007/ s10208-024-09679-2

  9. [9]

    Oudot, Marc Glisse, and Vin de Silva.The Structure and Stability of Persistence Modules

    Fr´ ed´ eric Chazal, Steve Y. Oudot, Marc Glisse, and Vin de Silva.The Structure and Stability of Persistence Modules. SpringerBriefs in Mathematics. Springer Verlag, 2016. URL: https://inria.hal.science/hal-01330678, doi:10. 1007/978-3-319-42545-0

  10. [10]

    Yuzhou Chen, Elena Sizikova, and Yulia R. Gel. TopoAttn-Nets: Topological Attention in Graph Representation Learning, pages 309–325. Springer International Publishing, 2023. doi:10.1007/978-3-031-26390-3_19 . 22 DA VID E. MU ˜NOZ, ELIZABETH MUNCH, FIRAS A. KHASA WNEH

  11. [11]

    Distances between directed networks and applications

    Samir Chowdhury and Facundo Memoli. Distances between directed networks and applications. In 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP). IEEE, March 2016. doi:10.1109/ icassp.2016.7472913

  12. [12]

    Persistent homology of directed networks

    Samir Chowdhury and Facundo Memoli. Persistent homology of directed networks. In 2016 50th Asilomar Confer- ence on Signals, Systems and Computers . IEEE, nov 2016. doi:10.1109/acssc.2016.7868997

  13. [13]

    A functorial Dowker theorem and persistent homology of asymmetric networks

    Samir Chowdhury and Facundo M´ emoli. A functorial Dowker theorem and persistent homology of asymmetric networks. Journal of Applied and Computational Topology , 2(1):115–175, 2018. doi:10.1007/s41468-018-0020-6

  14. [14]

    Persistent path homology of directed networks

    Samir Chowdhury and Facundo M´ emoli. Persistent path homology of directed networks. In Proceedings of the 2018 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA) , pages 1152–1169. ACM-SIAM,

  15. [15]

    URL: https://epubs.siam.org/doi/abs/10.1137/1.9781611975031.75, arXiv:https://epubs.siam.org/ doi/pdf/10.1137/1.9781611975031.75, doi:10.1137/1.9781611975031.75

  16. [16]

    Distances and isomorphism between networks: stability and conver- gence of network invariants

    Samir Chowdhury and Facundo M´ emoli. Distances and isomorphism between networks: stability and conver- gence of network invariants. Journal of Applied and Computational Topology , 7(2):243–361, 2023. doi:10.1007/ s41468-022-00105-6

  17. [17]

    Metric structures on networks and applications

    Samir Chowdhury and Facundo M´ emoli. Metric structures on networks and applications. In 2015 53rd Annual Allerton Conference on Communication, Control, and Computing (Allerton) , pages 1470–1472, 2015. doi:10. 1109/ALLERTON.2015.7447182

  18. [18]

    Pedro Concei¸ c˜ ao, Dejan Govc, J¯ anis Lazovskis, Ran Levi, Henri Riihim¨ aki, and Jason P. Smith. An application of neighbourhoods in digraphs to the classification of binary dynamics. Network Neuroscience, pages 1–24, may 2022. doi:10.1162/netn_a_00228

  19. [19]

    Dey, Tianqi Li, and Yusu Wang

    Tamal K. Dey, Tianqi Li, and Yusu Wang. An Efficient Algorithm for 1-Dimensional (Persistent) Path Homol- ogy. In Sergio Cabello and Danny Z. Chen, editors, 36th International Symposium on Computational Geometry (SoCG 2020), volume 164 of Leibniz International Proceedings in Informatics (LIPIcs), pages 36:1–36:15, Dagstuhl, Germany, 2020. Schloss Dagstuhl...

  20. [20]

    Computational Topology for Data Analysis

    Tamal K Dey and Yusu Wang. Computational Topology for Data Analysis . Cambridge University Press, 2021

  21. [21]

    C. H. Dowker. Homology groups of relations. The Annals of Mathematics, 56(1):84, jul 1952. doi:10.2307/1969768

  22. [22]

    Networks, crowds, and markets

    David Easley. Networks, crowds, and markets . Cambridge University Press, Cambridge, 2010

  23. [23]

    Persistent homology: theory and practice

    Herbert Edelsbrunner and Dmitriy Morozov. Persistent homology: theory and practice . eScholarship, University of California, 2013

  24. [24]

    Algorithms

    Jeff Erickson. Algorithms. S.N, S.L, 2019

  25. [25]

    Elementary Applied Topology

    Robert Ghrist. Elementary Applied Topology. 2014

  26. [26]

    Computing homotopy types of directed flag complexes

    Dejan Govc. Computing homotopy types of directed flag complexes. arXiv: Algebraic Topology, 2020. URL: https: //api.semanticscholar.org/CorpusID:219559236

  27. [27]

    Dejan Govc, Ran Levi, and Jason P. Smith. Complexes of tournaments, directionality filtrations and persistent homology. Journal of Applied and Computational Topology, 5(2):313–337, 2021. doi:10.1007/s41468-021-00068-0

  28. [28]

    Homologies of path complexes and digraphs,

    Alexander Grigor’yan, Yong Lin, Yuri Muranov, and Shing-Tung Yau. Homologies of path complexes and digraphs,

  29. [29]

    URL: https://arxiv.org/abs/1207.2834, arXiv:1207.2834

  30. [30]

    Graph filtration learning

    Christoph Hofer, Florian Graf, Bastian Rieck, Marc Niethammer, and Roland Kwitt. Graph filtration learning. In Hal Daum´ e III and Aarti Singh, editors, Proceedings of the 37th International Conference on Machine Learning , volume 119 of Proceedings of Machine Learning Research, pages 4314–4323. PMLR, 13–18 Jul 2020. URL: https: //proceedings.mlr.press/v1...

  31. [31]

    Topological graph neural networks

    Max Horn, Edward De Brouwer, Michael Moor, Yves Moreau, Bastian Rieck, and Karsten Borgwardt. Topological graph neural networks. InInternational Conference on Learning Representations, 2022. URL: https://openreview. net/forum?id=oxxUMeFwEHd

  32. [32]

    Ignacio and Isabel K

    Paul Samuel P. Ignacio and Isabel K. Darcy. Tracing patterns and shapes in remittance and migration networks via persistent homology. EPJ Data Science , 8(1):1, 2019. doi:10.1140/epjds/s13688-018-0179-z

  33. [33]

    Going beyond persistent homology using persistent homology

    Johanna Immonen, Amauri Souza, and Vikas Garg. Going beyond persistent homology using persistent homology. In A. Oh, T. Naumann, A. Globerson, K. Saenko, M. Hardt, and S. Levine, editors, Advances in Neural Information Processing Systems, volume 36, pages 63150–63173. Curran Associates, Inc., 2023. URL: https://proceedings. neurips.cc/paper_files/paper/20...

  34. [34]

    Persistent homology: state of the art and challenges

    Michael Kerber. Persistent homology: state of the art and challenges. International Mathematische Nachrichten , 231(15-33):1, 2016

  35. [35]

    Analysis of dynamic graphs and dynamic metric spaces via zigzag persistence

    Woojin Kim, Facundo M´ emoli, and Zane Smith. Analysis of dynamic graphs and dynamic metric spaces via zigzag persistence. In Topological Data Analysis, pages 371–389. Springer International Publishing, 2020. doi:10.1007/ 978-3-030-43408-3_14

  36. [36]

    Interleaving by parts: Join decompositions of interleavings and join-assemblage of geodesics

    Woojin Kim, Facundo M´ emoli, and Anastasios Stefanou. Interleaving by parts: Join decompositions of interleavings and join-assemblage of geodesics. Order, 41(2):497–537, 2024. doi:10.1007/s11083-023-09643-9

  37. [37]

    LaFontaine, M

    J. LaFontaine, M. Katz, M. Gromov, S.M. Bates, P. Pansu, P. Pansu, and S. Semmes. Metric Structures for Riemannian and Non-Riemannian Spaces . Modern Birkh¨ auser Classics. Birkh¨ auser Boston, 2007. URL: https: //books.google.com/books?id=QEJVUVJ9tMcC

  38. [38]

    Dynamic neural dowker network: Approximating persistent homology in dynamic directed graphs

    Hao Li, Hao Jiang, Fan Jiajun, Dongsheng Ye, and Liang Du. Dynamic neural dowker network: Approximating persistent homology in dynamic directed graphs. In Proceedings of the 30th ACM SIGKDD Conference on Knowl- edge Discovery and Data Mining, KDD ’24, page 1554–1564, New York, NY, USA, 2024. Association for Computing Machinery. doi:10.1145/3637528.3671980

  39. [39]

    Dowker complex based machine learning (DCML) models for protein-ligand binding affinity prediction

    Xiang Liu, Huitao Feng, Jie Wu, and Kelin Xia. Dowker complex based machine learning (DCML) models for protein-ligand binding affinity prediction. PLOS Computational Biology , 18(4):e1009943, apr 2022. doi:10.1371/ journal.pcbi.1009943. THE W ALK-LENGTH FILTRATION FOR PERSISTENT HOMOLOGY ON WEIGHTED DIRECTED GRAPHS 23

  40. [40]

    Smith, and Ran Levi

    Daniel L¨ utgehetmann, Dejan Govc, Jason P. Smith, and Ran Levi. Computing persistent homology of directed flag complexes. Algorithms, 13(1):19, jan 2020. doi:10.3390/a13010019

  41. [41]

    Filtered complexes

    Cl´ ement Maria. Filtered complexes. InGUDHI User and Reference Manual. GUDHI Editorial Board, 3.11.0 edition,

  42. [42]

    URL: https://gudhi.inria.fr/doc/3.11.0/group__simplex__tree.html

  43. [43]

    A user’s guide to topological data analysis

    Elizabeth Munch. A user’s guide to topological data analysis. Journal of Learning Analytics, 4(2), 2017. URL: http: //www.learning-analytics.info/journals/index.php/JLA/article/view/5196, doi:10.18608/jla.2017.42.6

  44. [44]

    James R. Munkres. Elements of Algebraic Topology. Addison Wesley, 1993

  45. [45]

    Khasawneh, and Elizabeth Munch

    Audun Myers, Firas A. Khasawneh, and Elizabeth Munch. Persistence of weighted ordinal partition networks for dynamic state detection. SIAM Journal on Applied Dynamical Systems , 22(1):65–89, feb 2023. arXiv:2205.08349, doi:10.1137/22m1476848

  46. [46]

    Beyer, R

    Audun Myers, Elizabeth Munch, and Firas A. Khasawneh. Persistent homology of complex networks for dy- namic state detection. Physical Review E , 100(2):022314, aug 2019. arXiv:1904.07403, doi:10.1103/PhysRevE. 100.022314

  47. [47]

    Myers, Max M

    Audun D. Myers, Max M. Chumley, Firas A. Khasawneh, and Elizabeth Munch. Persistent homology of coarse- grained state-space networks. Phys. Rev. E , 107:034303, Mar 2023. URL: https://link.aps.org/doi/10.1103/ PhysRevE.107.034303, arXiv:2206.02530, doi:10.1103/PhysRevE.107.034303

  48. [48]

    S´ anchez-Garc´ ıa

    David M´ endez and Rub´ en J. S´ anchez-Garc´ ıa. A directed persistent homology theory for dissimilarity functions. Journal of Applied and Computational Topology , 7(4):771–813, June 2023. doi:10.1007/s41468-023-00124-x

  49. [49]

    O’Keefe and J

    J. O’Keefe and J. Dostrovsky. The hippocampus as a spatial map. preliminary evidence from unit activity in the freely-moving rat. Brain Research, 34(1):171–175, 1971. URL: https://www.sciencedirect.com/science/article/ pii/0006899371903581, doi:https://doi.org/10.1016/0006-8993(71)90358-1

  50. [50]

    Reimann, Max Nolte, Martina Scolamiero, Katharine Turner, Rodrigo Perin, Giuseppe Chindemi, Pawel Dlotko, Ran Levi, Kathryn Hess, and Henry Markram

    Michael W. Reimann, Max Nolte, Martina Scolamiero, Katharine Turner, Rodrigo Perin, Giuseppe Chindemi, Pawel Dlotko, Ran Levi, Kathryn Hess, and Henry Markram. Cliques of neurons bound into cavities provide a missing link between structure and function. Frontiers in Computational Neuroscience , 11:48, 2017. URL: http: //journal.frontiersin.org/article/10....

  51. [51]

    A persistent weisfeiler–lehman procedure for graph classifi- cation

    Bastian Rieck, Christian Bock, and Karsten Borgwardt. A persistent weisfeiler–lehman procedure for graph classifi- cation. In Proceedings of the 36 th International Conference on MachineLearning, Long Beach, California, PMLR 97, 2019

  52. [52]

    Wasserstein stability for persistence diagrams

    Primoz Skraba and Katharine Turner. Wasserstein stability for persistence diagrams. June 2020. arXiv:2006.16824

  53. [53]

    Rips filtrations for quasi-metric spaces and asymmetric functions with stability results

    Katharine Turner. Rips filtrations for quasi-metric spaces and asymmetric functions with stability results. Algebraic & Geometric Topology, 19(3):1135–1170, August 2019. arXiv:1608.00365, doi:10.2140/agt.2019.19.1135

  54. [54]

    M¨ uller

    Florian Unger, Jonathan Krebs, and Michael G. M¨ uller. Simplex closing probabilities in directed graphs.Computa- tional Geometry, 109:101941, feb 2023. doi:10.1016/j.comgeo.2022.101941. Appendix A. Bounding the running time This lemma is used in Section 3.3 to bound the running time. The method largely follows a post 3 on stack overflow. Lemma A.1. For a...