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arxiv: 2605.16525 · v1 · pith:ZFDK4KUWnew · submitted 2026-05-15 · 🧮 math.AT

Mayer Path Homology

Pith reviewed 2026-05-19 21:24 UTC · model grok-4.3

classification 🧮 math.AT
keywords Mayer path homologyN-nilpotent differentialdirected graphspath complexeshomology groupsnetwork motifsdirected cyclesspanning trees
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The pith

Mayer path homology equips directed path complexes with an N-nilpotent differential to produce a finer invariant than standard path homology.

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

The paper constructs Mayer path homology by introducing an N-differential on path complexes of directed graphs. This yields homology groups that remain invariant under the directed structure yet separate network motifs indistinguishable by ordinary path homology. The authors classify the generators of the low-dimensional modules and express the one-cycles via weighted cycles built from spanning trees. A reader would care because the construction supplies a new algebraic lens for extracting higher-order directed information from graphs. The work focuses on establishing the basic structural properties of these groups rather than on computational examples.

Core claim

Equipping path complexes with an N-nilpotent differential produces N-chain complexes of ∂-invariant paths whose homology groups H_n^{N,q}(P) define a canonical invariant of directed graphs that is strictly more sensitive than classical path homology and distinguishes directed network motifs that ordinary path homology cannot separate.

What carries the argument

The N-nilpotent differential on path complexes, which generates N-chain complexes of ∂-invariant paths and the associated Mayer path homology groups.

If this is right

  • The construction distinguishes directed network motifs that ordinary path homology cannot separate.
  • All admissible combinatorial types of generators for Ω₂^N and Ω₃^N are classified.
  • Elements of the first Mayer path cycles group Z₁^{N,q} are characterized in terms of weighted directed cycles from spanning-tree constructions.

Where Pith is reading between the lines

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

  • The finer invariant could be applied to detect previously hidden directed patterns in biological or transportation networks.
  • Extending the classification to higher dimensions might reveal additional combinatorial constraints on admissible cycles.
  • The spanning-tree description of cycles suggests a possible algorithmic route for computing the groups on concrete graphs.

Load-bearing premise

The N-nilpotent differential produces well-defined homology groups that stay invariant under the directed graph structure and remain strictly finer than classical path homology.

What would settle it

Two non-isomorphic directed graphs that share the same Mayer path homology groups but differ in a motif that the paper claims the groups should detect.

Figures

Figures reproduced from arXiv: 2605.16525 by Dilan Karaguler, Guo-Wei Wei.

Figure 1
Figure 1. Figure 1: Examples of triangulations of the torus 4 [PITH_FULL_IMAGE:figures/full_fig_p004_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Example 3.1 For example, ∂(e123) = e23 + ξe13 + ξ 2 e12, where ξ is the N-th root of unity and e13 ̸∈ A1. Hence, (An, ∂) does not always form an N-chain complex. Definition 7. For N ≥ 2 and 1 ≤ q ≤ N − 1, define the space of ∂-invariant n-paths at level (N, q) as Ω N,q n = ΩN,q n (P) = {v ∈ An | ∂ q v ∈ An−q}. The intersection is called ∂-invariant n-paths and is denoted as follows: Ω N n = \ 1≤q≤N−1 Ω N,q… view at source ↗
Figure 3
Figure 3. Figure 3: Digraphs T1 and T2 in Example 3.3 Example 3.3. Let T1 and T2 be digraphs in [PITH_FULL_IMAGE:figures/full_fig_p010_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Digraphs used in Example 3.4 Example 3.4. Let L1, L2 and L3 be the digraphs as in [PITH_FULL_IMAGE:figures/full_fig_p011_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: The generators of ΩN 2 It was proven in [7] that any element of Ω2 2 of path complex induced by finite digraph G can be represented as a linear combination of double edge, triangle and square. There were no classification for higher chain structure in [7]. We will show that the structure of ΩN 2 is same with Ω2 2 . Theorem 3.2. Elements of Ω N 2 of path complex P(G) induced by finite digraph G can be repre… view at source ↗
Figure 6
Figure 6. Figure 6: Trapezohedron Tm basis [12]. Definition 9. A p-path v = Pv i0,··· ,ip ei0,··· ,ip is called (a, b)-cluster if all the elementary paths ei0,··· ,ip with nonzero coefficients have i0 = a and ip = b. A path is called cluster if it is a (a, b)- cluster for some a, b ∈ V (G). It is known that any p-path in Ω2 p is a sum of Ω2 p clusters [6] . We extend this to Mayer setting. Lemma 3.3. Any element v ∈ Ω N,1 n i… view at source ↗
Figure 7
Figure 7. Figure 7: Left to right. Top row: γ9, γ8, self-connections (γi , γi) for i = 1, 2, 4, 5, and the trape￾zohedron. Second row: connections (γi , γ7) introducing a new vertex for i = 1, 2, 4, 5. Third row: connections (γi , γ7) with repeated vertices for i = 1, 2, 4, 5. Fourth row: (γi , γi+3, γ7) with a new vertex and with a repeated vertex for i = 1, 2. Last row: connections (γ3, γ7), (γ6, γ7), and the chain (γ3, γ6,… view at source ↗
Figure 8
Figure 8. Figure 8: The digraph in the Example 3.5 For the families T1 and T2, there are two distinct realizations. These correspond to the two possible endpoint configurations of the alternating path. In one case, the endpoint components share three vertices, while in the other case they share only two vertices, even though no edge exists between them in Γ. Each configuration produces a distinct generator (a, b)-cluster. For… view at source ↗
read the original abstract

We introduce Mayer path homology, a new homology theory for directed path complexes obtained by equipping path complexes with an $N$-nilpotent differential. The main novelty of this work is the introduction of an $N$-differential on path complexes, giving rise to $N$-chain complexes of $\partial$-invariant paths and Mayer path homology groups $H_n^{N,q}(P)$. We prove that this construction defines a canonical invariant of directed graphs and is more sensitive than standard path homology, distinguishing directed network motifs that ordinary path homology cannot separate. We further establish a complete classification of generators of $\Omega_2^N$ and $\Omega_3^N$, determining all admissible combinatorial types. Finally, we characterize elements of the first Mayer path cycles group $Z_1^{N,q}$ in terms of weighted directed cycles arising from spanning-tree constructions. These results provide the first systematic structural theory for Mayer path complexes and reveal new higher-order algebraic structures in directed graphs.

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

1 major / 2 minor

Summary. The manuscript introduces Mayer path homology for directed path complexes by equipping them with an N-nilpotent differential. This yields N-chain complexes of ∂-invariant paths and the homology groups H_n^{N,q}(P). The paper claims to prove that the construction is a canonical invariant of directed graphs, strictly finer than classical path homology in distinguishing directed network motifs, provides a complete classification of generators for Ω_2^N and Ω_3^N, and characterizes the first Mayer path cycle group Z_1^{N,q} via weighted directed cycles obtained from spanning-tree constructions.

Significance. If the invariance under directed-graph isomorphisms and the claimed sensitivity hold, the construction would supply a new algebraic invariant capable of separating directed motifs invisible to ordinary path homology. The explicit combinatorial classification of low-dimensional generators and the spanning-tree characterization of cycles would constitute concrete structural results that could be useful for both theoretical work in algebraic topology and applications to directed networks.

major comments (1)
  1. [3] Section 3: The proof that H_n^{N,q} is invariant under directed-graph isomorphisms verifies only that the N-differential vanishes on generators of Ω_n. It does not separately confirm that every admissible path morphism—including those induced by graph automorphisms that permute higher-order paths—commutes with the N-power in the manner required to induce a well-defined map on homology. This compatibility is load-bearing for the central claim that the groups form a canonical invariant.
minor comments (2)
  1. The distinction between the N-differential and the ordinary boundary operator could be introduced with an explicit formula and a short example before the invariance argument begins.
  2. A brief comparison table or diagram illustrating a directed motif that is separated by Mayer path homology but not by standard path homology would strengthen the sensitivity claim.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the careful reading and constructive criticism of our manuscript on Mayer path homology. The major comment raises an important point about the completeness of the invariance argument, which we address directly below. We will revise the manuscript to incorporate an explicit verification of the required compatibility.

read point-by-point responses
  1. Referee: Section 3: The proof that H_n^{N,q} is invariant under directed-graph isomorphisms verifies only that the N-differential vanishes on generators of Ω_n. It does not separately confirm that every admissible path morphism—including those induced by graph automorphisms that permute higher-order paths—commutes with the N-power in the manner required to induce a well-defined map on homology. This compatibility is load-bearing for the central claim that the groups form a canonical invariant.

    Authors: We agree that the current exposition in Section 3 focuses primarily on showing that the N-differential vanishes on the generators of Ω_n and does not explicitly treat the commutation of arbitrary admissible path morphisms with the N-power of the differential. While the nilpotency and the definition of the N-chain complex ensure that the differential is well-defined on the subcomplex, an additional direct verification is needed to confirm that every graph isomorphism (and more generally every admissible path morphism) induces a chain map on the N-chain complexes. We will add a new lemma (Lemma 3.X) that proves φ ∘ ∂^N = ∂^N ∘ φ for any admissible path morphism φ by explicit computation on generators of the path complex, using the fact that φ preserves the boundary operator and the nilpotency condition. This lemma will be placed immediately before the invariance theorem and will establish that the induced maps on homology are well-defined, thereby confirming that H_n^{N,q} is a canonical invariant of directed graphs. We believe this addition fully resolves the concern without altering the main results. revision: yes

Circularity Check

0 steps flagged

Mayer path homology is a new construction with no reduction of invariants to fitted inputs or self-citations

full rationale

The paper defines an N-nilpotent differential on path complexes to produce Mayer path homology groups H_n^{N,q}(P) and proves these form a canonical invariant of directed graphs. All central objects (the N-differential, Ω_n^N, Z_1^{N,q}) are introduced as new definitions rather than derived from prior fitted quantities. No equation reduces a claimed prediction or invariant to a parameter fitted from the same data, and no load-bearing step rests on a self-citation chain that presupposes the result. The derivation is therefore self-contained; any questions about the completeness of the invariance proof under path morphisms concern correctness rather than circularity.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 1 invented entities

The work rests on the standard axioms of chain complexes and path homology plus the new domain assumption that an N-nilpotent differential can be consistently defined on directed path complexes. No free parameters or invented physical entities appear; the new homology groups are the primary added structure.

axioms (2)
  • domain assumption Path complexes admit an N-nilpotent differential that commutes appropriately with the existing boundary operator.
    This is the central new structure introduced in the abstract and is required for the definition of the N-chain complexes.
  • domain assumption The resulting homology groups are invariants of the underlying directed graph.
    Invariance is asserted as a proved property but functions as a background assumption for the theory to be useful.
invented entities (1)
  • Mayer path homology groups H_n^{N,q}(P) no independent evidence
    purpose: To provide a new homology invariant for directed path complexes.
    These groups are defined in the paper using the new N-differential.

pith-pipeline@v0.9.0 · 5684 in / 1321 out tokens · 57718 ms · 2026-05-19T21:24:39.481057+00:00 · methodology

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Reference graph

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