Can a Few Echoes Reveal a Hidden Arithmetic Shape?

The laboratory uses the primes 2, 3 and 5. A synthetic object has 64 components, n = 2^a 3^b 5^c with a, b, c in {0,1,2,3}. Each prime has a four-level profile. For a prime p, the shape coordinate y_p is converted to u_p = y_p/(1-y_p) and q_p(a) = u_p^a/(1+u_p+u_p^2+u_p^3). The coefficient of a component is q_2(a)q_3(b)q_5(c).

Shape means an exponent-weight profile. It is not the physical shape of a prime and the primes do not move: y_p below one half favors low exponents, one half makes the four levels even, and y_p above one half favors high exponents.

The instrument does not read the 64 components separately. At time t it hears H_y(t), the product over p in {2,3,5} of the four-term harmonic sums exp(-i a t log p). The displayed three-reading schedule is the phase-separated schedule certified in Arithmetic Observability V.

Sources: [1] [3]

Two shapes are exactly observationally equivalent for a chosen schedule when all displayed readings agree. With uncertainty, the useful question is whether their possible response sets overlap. That overlap is called confusability; it is not treated as a transitive equivalence relation.

The laboratory uses a pairwise reading-space distance. If each object may carry independent adversarial error of radius epsilon, response fibres can meet when noiseless readings are within 2 epsilon. This is why the control is labelled Pair cutoff (2epsilon), written on the page as Pair cutoff (2ε).

The heatmap varies visible prime-2 and prime-3 shapes while the hidden prime-5 shape compensates as well as it can. Orange hatching marks displayed cells within the declared cutoff. One reading leaves broad cancellation valleys; independent readings cut across them.

Sources: [1] [2]

The second plot samples the smallest response change found for each displayed size of hidden-shape change. A low envelope means that some substantially different shapes remain nearly alike at that resolution; a rising envelope means larger changes force larger observed changes.

This curve is a sampled diagnostic, not a new theorem, not an energy spectrum and not a formal certificate. Its purpose is to make the exact theorem's geometry visible without pretending that a finite visualization covers the full continuous model.

Sources: [1]

An engineered quantum toy system can assign E_(a,b,c) = hbar Omega (a log 2 + b log 3 + c log 5) to basis state |a,b,c⟩. With the factorized occupation profile q_2(a)q_3(b)q_5(c), its survival amplitude reproduces the harmonic reading after a time rescaling.

This is a controlled mathematical embedding: the prime logarithms are chosen spectral spacings, the shape coordinates control occupation bias, and the reading times are design choices. It is not evidence that elementary particles naturally have prime-logarithmic energies. The sampled separation envelope is not an energy spectrum or a formal certificate.

Possible future analogies include quantum sensing, spectroscopy, network diagnostics, structured mixtures and distributed sensing, but any physical application would require its own calibration and validation.

Sources: [1]

Observability is a relationship among the hidden model, the feature we want, the allowed measurements, the nuisance changes we permit and the metric in which error is judged. Change any one of these and the boundary between distinguishable and confusable can move.

The Atlas turns that boundary into kernel criteria, reading counts, minimax constants, quotient metrics, compact phase geometries, response tubes, zonoids and certified finite examples. The durable lesson is that a protocol helps determine which directions are near, which are far and which collapse into an observable shadow.

Sources: [2]

The AO Lab is a dependency-free interactive illustration of a declared synthetic model. It makes no external requests. The formal Atlas remains the authority for the full model map and open arithmetic-realizability boundary; Arithmetic Observability V is the authority for the exact three-reading theorem. Other Atlas branches use different models, norms and nuisance classes.

The immutable companion source is commit 6d9058a in the public repository. The corpus verifier passed with payload a64f515f770d316a3d6ecad4b70494af1a5cc90342b4076c7fd783fce0f1c0d6. Focused corpus tests were 51/51; the broader AO suite was 332 passing with one intentional AO-IX opt-in rebuild skip.

• python arithmetic_observability_corpus.py arithmetic_observability_corpus_manifest.json
• python -m unittest -q test_arithmetic_observability_corpus.py
• python -m unittest discover -s . -p 'test_arithmetic_observability*.py' -q

Sources: [1] [4] [5]