Persistent Homology

Holes, loops, connected components, topological persistence
topologicaldim topological8 metrics

What It Measures

How many holes and connected components survive as you zoom out -- the topological skeleton that persists across scales.

Delay-embeds the signal into 2D, deduplicates the point cloud, then builds a Vietoris-Rips filtration: imagine inflating a ball around every point and tracking when components merge (H0) and when loops form and fill in (H1). Features that persist across a wide range of scales are topologically robust. Features that blink in and out are noise. The distribution of lifetimes, their entropy, and the total persistence mass characterize the signal's topological complexity.

Metrics

n_significant_features

Count of H0 features with lifetime above 0.1. Dice Rolls (34.1) produces the most significant components -- its random jumps create many well-separated clusters that merge at different scales. Intermittent Silence (24.9) and Collatz Stopping Times (20.8) follow. Rössler (1.0) has just one significant component -- its attractor is a single connected blob in the delay embedding.

h1_total_persistence

Total lifetime mass of all H1 (loop) features. Dice Rolls (1.83) dominates, with loops forming at many scales as its scattered point cloud creates ring-like structures during filtration. Collatz Gap Lengths (0.56) and Codon Usage (0.54) have modest loop structure. Logistic Chaos and Tent Map score 0.0 -- their dense, space-filling attractors leave no room for persistent loops.

max_h1_lifetime

Lifetime of the single most persistent loop. Rule 30 (0.414), Symbolic Lorenz (0.414), and Morse Code (0.414) share the top score -- their binary-valued signals create specific point-cloud geometries in delay embedding where one dominant loop persists across scales. This metric identifies signals with a single robust circular or toroidal structure.

max_components

Total number of H0 features (connected components at birth). Solar Wind IMF and Solar Wind Speed both score 50, meaning their delay embeddings start as 50 isolated clusters before merging. Quantum Walk scores 1.0 -- its encoding produces a nearly connected point cloud from the start.

persistence_entropy

Shannon entropy of the lifetime distribution. High entropy means the topological features have diverse lifetimes (no single scale dominates). Low entropy means one feature dominates all others. This separates multi-scale signals from those with a single characteristic scale.

max_lifetime

Lifetime of the single most persistent H0 feature (connected component). Dice Rolls, L-System Dragon, and Rule 110 all hit 1.414 (= sqrt(2), the maximum distance in the unit square delay embedding). Henon Near-Crisis (0.75) has the shortest maximum lifetime — its attractor is compact, so the last two components merge early. This measures the geometric diameter of the delay-embedded point cloud.

n_h1_features

Average number of H1 (loop) features per trial. Poker Hands (2.5) and Nikkei Returns (2.2) produce the most loops — their scattered point clouds create ring-like structures during filtration. Logistic Chaos and Tent Map score 0.0 (dense, space-filling attractors with no persistent loops). This counts genuine circular or toroidal topology in the delay embedding.

total_persistence

Sum of all H0 feature lifetimes. Dice Rolls (8.04) has the highest total — many well-separated clusters, each persisting for a long time. Constants and Quantum Walk score 1.0 (a single component with unit lifetime). This is an integral measure of topological complexity: it weights both the number and duration of connected components.

Atlas Rankings

h1_total_persistence
SourceDomainValue
Dice Rollsexotic1.8348
Poisson Countsexotic0.8194
Collatz Gap Lengthsnumber_theory0.6094
···
Logistic Chaoschaos0.0000
Tent Mapchaos0.0000
Constant 0xFFnoise0.0000
max_components
SourceDomainValue
Solar Wind IMFastro50.0000
Solar Wind Speedastro50.0000
Sunspot Numberastro50.0000
···
Constant 0xFFnoise1.0000
Quantum Walkquantum1.0000
Square Wavewaveform1.6000
max_h1_lifetime
SourceDomainValue
L-System (Dragon Curve)exotic0.4142
Morse Codewaveform0.4142
Rule 110exotic0.4142
···
Logistic Chaoschaos0.0000
Tent Mapchaos0.0000
Constant 0xFFnoise0.0000
max_lifetime
SourceDomainValue
Dice Rollsexotic1.4142
Symbolic Lorenzexotic1.4142
Fibonacci Wordexotic1.4142
···
Noisy Period-2chaos0.6625
Henon Near-Crisis (a=1.2)chaos0.7467
Logistic r=3.68 (Banded Chaos)chaos0.7671
n_h1_features
SourceDomainValue
Nikkei Returnsfinancial2.2000
Categorical Sensorexotic2.2000
NASDAQ Returnsfinancial2.1200
···
Logistic Chaoschaos0.0000
Tent Mapchaos0.0000
Prime Gapsnumber_theory0.0000
n_significant_features
SourceDomainValue
Dice Rollsexotic34.1333
Intermittent Silenceexotic24.8667
Markov Chain (10-state)exotic22.4800
···
Rossler Attractorchaos1.0000
Constant 0x00noise1.0000
Sine Wavewaveform1.0000
persistence_entropy
SourceDomainValue
Poisson Countsexotic5.1900
Temperature Driftclimate5.0796
Human Proteomebio5.0429
···
Constant 0xFFnoise0.0000
Quantum Walkquantum0.0000
PID Controllerexotic0.2878
total_persistence
SourceDomainValue
Dice Rollsexotic8.0409
Devil's Staircaseexotic6.3804
Markov Chain (10-state)exotic6.1952
···
Constant 0xFFnoise1.0000
Quantum Walkquantum1.0000
PID Controllerexotic1.2037

When It Lights Up

Persistent Homology is the atlas's most direct topological detector. The n_significant_features metric uniquely identifies signals with complex multi-component structure -- Dice Rolls, Intermittent Silence, and Collatz Stopping Times form a cluster that no other geometry highlights. The H1 metrics separate signals with genuine loop topology from those that are simply connected, a distinction only available through filtration-based analysis.

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