Mostow Rigidity

Geometric rigidity, volume invariance, Margulis thickness
topologicaldim 36 metrics

What It Measures

Whether your signal's geometry is locked in place or free to deform -- the difference between a crystal and a liquid.

Embeds byte triples into the 3D Poincaré ball, forms tetrahedra, and then asks: if you shake the data slightly, does the hyperbolic geometry change? Mostow's rigidity theorem says that in dimension 3 and above, the shape of a hyperbolic manifold is completely determined by its topology -- there are no continuous deformations. This geometry tests the discrete analog: whether small perturbations (5% Gaussian noise) alter the distance structure, volume distribution, and spectral properties.

Metrics

distance_rigidity

Correlation between the original and perturbed pairwise distance matrices. Rule 30 (0.985) and Symbolic Lorenz (0.984) are nearly rigid: shaking the input barely changes the distances. This means their structure is determined by the combinatorial pattern, not the exact byte values. Constants score 0.0 (no distances to correlate).

volume_entropy

Shannon entropy of the hyperbolic tetrahedron volume distribution. Beta Noise (4.52), XorShift32 (4.50), and Dice Rolls (4.50) produce the most varied volumes -- their points fill the ball uniformly, creating tetrahedra of many different sizes. Logistic Period-2 (0.0) produces identical tetrahedra.

volume_rigidity

How stable is the total hyperbolic volume under perturbation? AES Encrypted (0.97) and Gzip (0.96) are volume-rigid: noise barely changes their total volume. Lorenz and Rössler Attractors score 0.0 -- their attractor geometry is sensitive to perturbation, the volumes shift substantially.

margulis_ratio

Ratio of 5th-percentile to 95th-percentile pairwise distances. Measures the gap between thin and thick parts of the geometry. Logistic Period-2 (1.0) has perfectly uniform spacing. Pulse-Width Mod (0.91) is nearly uniform. Low values mean the signal has both tightly clustered and widely separated regions.

spectral_rigidity

Correlation between Laplacian eigenvalues before and after perturbation. L-System Dragon (1.0), Morse Code (1.0), and Symbolic Henon (1.0) have perfectly stable spectra -- their graph connectivity pattern is insensitive to small perturbations. Logistic Period-3 (0.33) has a fragile spectrum.

mean_turn_angle

Average angular change between consecutive tetrahedra in the hyperbolic embedding. Logistic period-3 (1.0) and constants (1.0) have maximal turn angles (the trajectory makes sharp turns between tetrahedra). Beta Noise (0.04) and Logistic Chaos (0.07) have near-zero turn angles (smooth, gradual trajectory through hyperbolic space). This measures the "jerkiness" of the hyperbolic path.

Atlas Rankings

distance_rigidity
SourceDomainValue
Rule 30exotic0.9848
Kolakoski Sequenceexotic0.9844
Symbolic Lorenzexotic0.9843
···
Logistic r=3.83 (Period-3 Window)chaos0.0000
Critical Transition (Fold)chaos0.0152
Aubry-André Criticalquantum0.0361
margulis_ratio
SourceDomainValue
Logistic r=3.2 (Period-2)chaos1.0000
Square Wavewaveform0.9801
Pell Wordexotic0.9247
···
Logistic r=3.83 (Period-3 Window)chaos0.0000
Sine Map (Feigenbaum)chaos0.0000
Anderson 1D Localizedquantum0.0000
mean_turn_angle
SourceDomainValue
Logistic r=3.83 (Period-3 Window)chaos1.0000
Square Wavewaveform0.9893
Mian-Chowlanumber_theory0.9868
···
Beta Noisenoise0.0408
Quartic Map (Feigenbaum)chaos0.0535
Partition Functionnumber_theory0.0596
spectral_rigidity
SourceDomainValue
Moebius Functionnumber_theory1.0000
DNA Plasmodiumbio1.0000
L-System (Dragon Curve)exotic1.0000
···
Logistic r=3.83 (Period-3 Window)chaos0.3392
Aubry-André Criticalquantum0.5348
Mian-Chowlanumber_theory0.6197
volume_entropy
SourceDomainValue
Beta Noisenoise4.5192
Partition Functionnumber_theory4.5154
Dice Rollsexotic4.5058
···
Devil's Staircaseexotic0.0000
Logistic r=3.83 (Period-3 Window)chaos0.0000
Logistic r=3.2 (Period-2)chaos0.0000
volume_rigidity
SourceDomainValue
Moebius Functionnumber_theory0.9741
AES Encryptedbinary0.9699
Golden Ratio Digitsnumber_theory0.9685
···
Temperatureclimate0.0000
LIGO Livingstonastro0.0000
Accel Sitmotion0.0000

When It Lights Up

Mostow Rigidity uniquely separates signals whose geometric structure is topologically determined from those that are metrically flexible. The volume_rigidity metric cleanly splits encrypted/compressed data (rigid, 0.96+) from dynamical attractors (flexible, near 0.0) -- a distinction no other geometry captures. The distance_rigidity metric at the top is dominated by cellular automata and symbolic dynamics, signals whose structure is entirely combinatorial.

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