An improved upper bound measure of star complexity of graphs
Pith reviewed 2026-05-15 14:24 UTC · model grok-4.3
The pith
A tighter upper bound on star complexity from logic circuit optimization produces a more linear relationship with information complexity.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Exploiting the ABC package for logic circuit optimization supplies a strictly tighter upper bound on the circuit complexity variant of star complexity. When this bound is computed for 1000 Erdős-Renyi graphs on 500 vertices, the relationship to information-based complexity becomes more linear than with the previous proxy.
What carries the argument
ABC-based circuit optimization bound, which estimates the minimum logic circuit size needed to represent the graph and thereby upper-bounds its star complexity.
If this is right
- Star complexity of graphs can be bounded more tightly by repurposing existing logic-circuit optimizers.
- The relationship between star complexity and information-based complexity is closer to linear once the circuit variant is measured correctly.
- Numerical estimation of star complexity becomes feasible for graphs with hundreds of vertices.
- The distinction between circuit and formula complexity matters for the observed linearity in these measures.
Where Pith is reading between the lines
- The same optimizer-driven approach might be tested on other random-graph ensembles or on structured graphs to check whether linearity persists.
- If the bound remains useful, it could serve as a practical surrogate when exact star complexity is intractable.
- Hybrid measures that combine ABC bounds with information-theoretic quantities might further tighten estimates of computational cost.
Load-bearing premise
The ABC package produces a valid and strictly tighter upper bound on the circuit complexity of the graphs, and the modified graph walking algorithm accurately captures the circuit complexity variant rather than formula complexity.
What would settle it
Applying the new ABC-based measure to the same 1000 graphs and obtaining a correlation with information complexity that is no more linear than the earlier proxy, or finding concrete graphs where the bound exceeds the true star complexity.
Figures
read the original abstract
In \cite{Standish25c}, I explored the connection between star complexity and information based complexity. Because of the numerical difficulty in computing star complexity, I introduced a proxy measure that is an upper bound to star complexity, and showed a strong albeit non-linear relationship between the measures. In this paper, I introduce a tighter upper bound, by exploiting the well-known ABC package used to optimise logic circuits. In testing the new measure, I found that I had been computing the {\em formula complexity} variant of star complexity, rather than the tighter {\em circuit complexity} variant. Since Jukna clearly states the connection between star complexity and circuit complexity, I have modified the graph walking algorithm to capture circuit complexity rather than formula complexity. With this new ABC-based measure, applied to a set of 1000 500 vertex Erd\"os-Renyi graphs, a more linear relationship between star complexity and information based complexity is found.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript claims to introduce a tighter upper bound on star complexity of graphs by integrating the ABC logic circuit optimization package, corrects the prior proxy (which computed formula complexity) by modifying the graph-walking algorithm to target the circuit complexity variant with gate sharing, and reports a more linear empirical relationship with information-based complexity when evaluated on 1000 Erdős-Rényi graphs of 500 vertices.
Significance. If the ABC integration produces a rigorously valid and strictly tighter upper bound and the algorithm modification correctly enforces sharing while remaining an upper bound on star-cover size, the work supplies a practical, scalable proxy that strengthens the observed link between star complexity and information complexity, facilitating further empirical and theoretical study of these measures on large graphs.
major comments (3)
- [Abstract] Abstract and method description: the assertion that the graph-walking algorithm was modified to capture circuit complexity (with sharing) rather than formula complexity is not accompanied by any pseudocode, precise description of the change, or small-graph validation showing how reuse is now permitted while still upper-bounding star-cover size; without this, it is impossible to confirm the new numbers are closer to circuit complexity.
- [Method] ABC integration: no details are supplied on how ABC-optimized circuits are converted into the numerical upper bound on star complexity, nor is any argument or small-instance comparison given establishing that the bound is strictly tighter than the previous proxy and remains a valid upper bound.
- [Results] Empirical results: the claim of a 'more linear relationship' on the 1000 graphs lacks quantitative support (e.g., correlation coefficients or R² values before versus after the change) and does not reference any table or figure that would allow assessment of the improvement.
Simulated Author's Rebuttal
We thank the referee for the constructive comments. We address each major point below and will revise the manuscript to provide the requested details, descriptions, and quantitative support.
read point-by-point responses
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Referee: [Abstract] Abstract and method description: the assertion that the graph-walking algorithm was modified to capture circuit complexity (with sharing) rather than formula complexity is not accompanied by any pseudocode, precise description of the change, or small-graph validation showing how reuse is now permitted while still upper-bounding star-cover size; without this, it is impossible to confirm the new numbers are closer to circuit complexity.
Authors: We agree that the current description of the algorithm modification is insufficient. In the revised manuscript we will add a precise textual description of the changes that enable gate sharing, include pseudocode for the updated graph-walking procedure, and provide a small-graph example that demonstrates permitted reuse while preserving the upper-bound property on star-cover size. revision: yes
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Referee: [Method] ABC integration: no details are supplied on how ABC-optimized circuits are converted into the numerical upper bound on star complexity, nor is any argument or small-instance comparison given establishing that the bound is strictly tighter than the previous proxy and remains a valid upper bound.
Authors: We acknowledge the omission. The revision will expand the method section with a step-by-step account of how ABC-optimized circuits are mapped to the numerical upper-bound value, supply a short argument establishing strict improvement over the prior proxy, and include explicit small-instance comparisons confirming both tightness and continued validity as an upper bound. revision: yes
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Referee: [Results] Empirical results: the claim of a 'more linear relationship' on the 1000 graphs lacks quantitative support (e.g., correlation coefficients or R² values before versus after the change) and does not reference any table or figure that would allow assessment of the improvement.
Authors: The referee correctly notes the absence of quantitative metrics. We will add correlation coefficients and R² values comparing the pre- and post-change relationships, and will insert explicit references to the supporting tables and figures in the results text. revision: yes
Circularity Check
No significant circularity; empirical linearity is observational
full rationale
The paper's central result is an empirical observation: applying an external ABC-based upper-bound proxy (distinct from the author's prior proxy) to 1000 random graphs yields a more linear relationship with information-based complexity. The modification to the graph-walking algorithm is asserted without equations or self-referential derivation that would force the outcome by construction. No step reduces a claimed prediction to a fitted parameter or to a self-citation chain; the relationship is tested on fresh data rather than being tautological. Self-citation to the author's earlier work supports only the historical context, not the new bound or linearity claim.
Axiom & Free-Parameter Ledger
Reference graph
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ABC optimised star complexity upper bound, StarABC (G) ABC is a package for optimisation and validation of logic circuits[ 8,9]. To use it, we used the C API to create a single-valued logic function with n boolean inputs, where n is the number of vertices. Initially , this was seeded with the or of all stars covered by the graph, and the remaining edges i...
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[4]
The results can be seen in figure ER-500
StarABC versus C of randomly generated Erdös-Renyi graphs We repeat the experiment outlined in [ 1], generating 1000 500-vertex Erdös-Renyi graphs (instead of the 1000-vertex graphs generated in [ 1]), and computing C, the im- proved Star and StarABC . The results can be seen in figure ER-500. As expected, StarABC is a much tighter upper bound than the ori...
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[5]
Conclusion In this paper, we explore estimating star complexity of graphs by means of the ABC package, widely used for optimising electronic logic circuits. It proves to be a more accu- rate estimate of star complexity than the proposal in [ 1], and also demonstrates an even stronger relationship between star complexity and information based complexity
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[6]
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