EVE-AEQIRION / research /code /test_separable_completion.py
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Release AËQIRION v3.0: manuscript, proofs, code and verification data
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#!/usr/bin/env python3
"""Exact finite checks for marginal kernels and separable coding obstructions.
Only standard-library integers and fractions. These checks do not prove
all-dimension statements or literature priority; proofs are in the manuscript.
"""
from fractions import Fraction as F
from itertools import product, combinations
from math import prod
import json
import random
def points(shape):
return list(product(*(range(q) for q in shape)))
def dot(a, b):
return sum((x * y for x, y in zip(a, b)), F(0))
def rank(rows):
if not rows:
return 0
a = [list(map(F, row)) for row in rows]
nr, nc = len(a), len(a[0])
pivot = 0
for j in range(nc):
found = next((i for i in range(pivot, nr) if a[i][j]), None)
if found is None:
continue
a[pivot], a[found] = a[found], a[pivot]
value = a[pivot][j]
a[pivot] = [x / value for x in a[pivot]]
for i in range(pivot + 1, nr):
if a[i][j]:
factor = a[i][j]
a[i] = [x - factor * y for x, y in zip(a[i], a[pivot])]
pivot += 1
if pivot == nr:
break
return pivot
def marginal_matrix(shape):
xs = points(shape)
rows = []
descriptors = []
for i in range(len(shape)):
other = [j for j in range(len(shape)) if j != i]
for assignment in product(*(range(shape[j]) for j in other)):
row = [int(all(x[j] == a for j, a in zip(other, assignment))) for x in xs]
rows.append(row)
descriptors.append((i, other, assignment))
return rows, descriptors
def matvec(a, x):
return [dot(row, x) for row in a]
def transpose_matvec(a, x):
return [sum((a[i][j] * x[i] for i in range(len(a))), F(0))
for j in range(len(a[0]))]
def one_factor_basis(q):
# Orthogonal integer Helmert contrasts; no square roots are approximated.
out = [[F(1)] * q]
for a in range(1, q):
out.append([F(1 if x < a else -a if x == a else 0) for x in range(q)])
for i, u in enumerate(out):
for v in out[:i]:
assert dot(u, v) == 0
return out
def tensor_vector(shape, basis, labels):
return [F(prod(basis[i][labels[i]][x[i]] for i in range(len(shape))))
for x in points(shape)]
def center_coordinate(shape, values, coordinate):
xs = points(shape)
lookup = dict(zip(xs, values))
out = []
for x in xs:
total = F(0)
for a in range(shape[coordinate]):
y = list(x)
y[coordinate] = a
total += lookup[tuple(y)]
out.append(total / shape[coordinate])
return out
def observable_from_marginals(shape, sums):
"""Reconstruct (I-P_K)z using inclusion-exclusion of averaging maps.
The input consists only of actual codimension-one sums; no original z
or hidden tensor coefficients are available to this decoder.
"""
a, descriptions = marginal_matrix(shape)
xs = points(shape)
one_coordinate_averages = []
for i in range(len(shape)):
entries = {}
for value, (coord, other, assignment) in zip(sums, descriptions):
if coord == i:
entries[assignment] = value / shape[i]
other = [j for j in range(len(shape)) if j != i]
one_coordinate_averages.append([entries[tuple(x[j] for j in other)] for x in xs])
out = [F(0)] * len(xs)
for size in range(1, len(shape) + 1):
for subset in combinations(range(len(shape)), size):
value = one_coordinate_averages[subset[0]]
for i in subset[1:]:
value = center_coordinate(shape, value, i)
sign = 1 if size % 2 else -1
out = [x + sign * y for x, y in zip(out, value)]
assert matvec(a, out) == sums
return out
def check_spectrum():
reports = []
count = 0
for shape in ((2, 2), (3, 3), (4, 4), (2, 3, 4), (3, 3, 3)):
a, _ = marginal_matrix(shape)
basis = [one_factor_basis(q) for q in shape]
null_count = 0
spectral_multiplicity = {}
for labels in product(*(range(q) for q in shape)):
v = tensor_vector(shape, basis, labels)
expected_eigenvalue = sum(q for q, label in zip(shape, labels) if label == 0)
lhs = transpose_matvec(a, matvec(a, v))
assert lhs == [expected_eigenvalue * x for x in v]
spectral_multiplicity[expected_eigenvalue] = spectral_multiplicity.get(
expected_eigenvalue, 0) + 1
null_count += expected_eigenvalue == 0
count += 1
expected_nullity = prod(q - 1 for q in shape)
actual_rank = rank(a)
assert null_count == expected_nullity
assert actual_rank == prod(shape) - expected_nullity
assert min(e for e in spectral_multiplicity if e) == min(shape)
reports.append({"shape": list(shape), "N": prod(shape),
"rank": actual_rank, "kernel_dimension": expected_nullity,
"gram_eigenvalues_and_multiplicities": spectral_multiplicity})
return {"exact_eigenvector_cases": count, "shapes": reports}
def check_separable_channels():
reports = []
for shape in ((2, 2), (3, 3), (4, 4), (2, 3, 4), (3, 4, 4), (3, 3, 3)):
a, _ = marginal_matrix(shape)
xs = points(shape)
for m in range(1, min(shape) + 1):
stacked = []
coordinate_ranks = []
for q in shape:
coordinate_ranks.append(rank([[(x + 1) ** j for x in range(q)]
for j in range(m)]))
for j in range(m):
# All coordinate factors are strictly positive Vandermonde rows.
mask = [prod((x[i] + 1) ** j for i in range(len(shape))) for x in xs]
assert min(mask) > 0
stacked.extend([[F(value) * weight for value, weight in zip(row, mask)]
for row in a])
expected_nullity = prod(q - r for q, r in zip(shape, coordinate_ranks))
actual_nullity = prod(shape) - rank(stacked)
assert actual_nullity == expected_nullity
assert expected_nullity == prod(max(q - m, 0) for q in shape)
reports.append({"shape": list(shape), "channels": m,
"coordinate_ranks": coordinate_ranks,
"joint_nullity": actual_nullity})
# Repeating a proportional channel adds no information.
repeated = a + [[3 * x for x in row] for row in a]
assert rank(repeated) == rank(a)
# Highlighted strict obstructions and their exact endpoints.
summary = {(tuple(r['shape']), r['channels']): r['joint_nullity'] for r in reports}
assert summary[((3, 3), 2)] == 1 and summary[((3, 3), 3)] == 0
assert summary[((4, 4), 3)] == 1 and summary[((4, 4), 4)] == 0
assert summary[((2, 3, 4), 2)] == 0
return {"stacked_rank_cases": len(reports),
"proportional_channel_counterexamples": 6, "cases": reports}
def check_scalar_completion():
rng = random.Random(20102026)
completed = probe_count = orthogonality_checks = null_probe_tests = 0
examples = []
for shape in ((2, 2), (3, 3), (4, 4), (2, 3, 4), (3, 3, 3)):
a, _ = marginal_matrix(shape)
basis = [one_factor_basis(q) for q in shape]
hidden = [tensor_vector(shape, basis, labels)
for labels in product(*(range(1, q) for q in shape))]
expected_d = prod(q - 1 for q in shape)
assert len(hidden) == expected_d
for i, u in enumerate(hidden):
assert matvec(a, u) == [0] * len(a)
for v in hidden[:i]:
assert dot(u, v) == 0
orthogonality_checks += 1
for repetition in range(4):
z = [F(rng.randrange(1, 100), rng.randrange(1, 20))
for _ in range(prod(shape))]
sums = matvec(a, z)
visible = observable_from_marginals(shape, sums)
for h in hidden:
assert dot(h, visible) == 0
total = sum(sums[:prod(shape) // shape[0]], F(0))
assert total == sum(z, F(0))
out = list(visible)
for h in hidden:
alpha = F(1, 1 + max(map(abs, h)))
mask = [1 + alpha * x for x in h]
assert min(mask) > 0 and max(mask) < 2
assert sum(mask, F(0)) == prod(shape)
measured = dot(mask, z)
coefficient = (measured - total) / (alpha * dot(h, h))
out = [x + coefficient * y for x, y in zip(out, h)]
probe_count += 1
assert out == z
completed += 1
# Omitting one orthogonal completion leaves a concrete positive
# indistinguishable pair, illustrating the general rank lower bound.
omitted = repetition % len(hidden)
delta = min(z) / (2 * max(map(abs, hidden[omitted])))
alternative = [x + delta * y for x, y in zip(z, hidden[omitted])]
assert min(alternative) > 0 and alternative != z
assert matvec(a, alternative) == sums
for i, h in enumerate(hidden):
if i != omitted:
assert dot(h, alternative) == dot(h, z)
null_probe_tests += 1
examples.append({"shape": list(shape), "necessary_and_sufficient_extra_scalars": expected_d})
return {"positive_tensor_reconstructions": completed,
"positive_mask_scalar_probes": probe_count,
"orthogonality_checks": orthogonality_checks,
"missing_probe_nonuniqueness_examples": null_probe_tests,
"dimensions": examples}
def check_bounded_fourier_completion():
"""Exact fourth-root-of-unity cases of the general Fourier construction.
Shapes use only 2 and 4, so real/imaginary character values are integers;
no trigonometric approximation or complex floating point is involved.
"""
reports = []
noise_equalities = 0
rho = F(1, 2)
roots = ((1, 0), (0, 1), (-1, 0), (0, -1))
for shape in ((2, 2), (4, 4), (2, 4, 4), (4, 4, 4)):
xs = points(shape)
a, _ = marginal_matrix(shape)
contrasts = []
for frequency in product(*(range(1, q) for q in shape)):
conjugate = tuple((-k) % q for k, q in zip(frequency, shape))
if frequency > conjugate:
continue
real, imag = [], []
for x in xs:
phase = sum((4 // q) * k * xi for q, k, xi in zip(shape, frequency, x)) % 4
re, im = roots[phase]
real.append(F(re))
imag.append(F(im))
contrasts.append(real)
if frequency != conjugate:
contrasts.append(imag)
assert len(contrasts) == prod(q - 1 for q in shape)
for i, h in enumerate(contrasts):
assert matvec(a, h) == [0] * len(a)
assert dot(h, h) in (prod(shape), F(prod(shape), 2))
for other in contrasts[:i]:
assert dot(h, other) == 0
z = [F(2 + (i * 7) % 23, 5) for i in range(prod(shape))]
visible = observable_from_marginals(shape, matvec(a, z))
total = sum(z, F(0))
reconstructed = list(visible)
for h in contrasts:
mask = [1 + rho * x for x in h]
assert min(mask) >= F(1, 2) and max(mask) <= F(3, 2)
coefficient = (dot(mask, z) - total) / (rho * dot(h, h))
reconstructed = [x + coefficient * y for x, y in zip(reconstructed, h)]
assert reconstructed == z
# Single-coordinate noise on a non-self-conjugate mode attains the
# uniform sqrt(2/N)/rho bound. Binary-only shapes have the stronger one.
target = min(contrasts, key=lambda h: dot(h, h))
epsilon = F(1, 1000)
perturbation = [epsilon * x / (rho * dot(target, target)) for x in target]
actual_error_squared = dot(perturbation, perturbation)
exact_bound_squared = epsilon ** 2 / (rho ** 2 * dot(target, target))
assert actual_error_squared == exact_bound_squared
if dot(target, target) == F(prod(shape), 2):
assert actual_error_squared == 2 * epsilon ** 2 / (rho ** 2 * prod(shape))
noise_equalities += 1
reports.append({"shape": list(shape), "positive_probes": len(contrasts),
"minimum_contrast_norm_squared": str(dot(target, target)),
"recovered_exactly": True})
return {"exact_fourier_cases": len(reports),
"sharp_noise_equalities": noise_equalities, "cases": reports}
def run():
return {"status": "PASS", "arithmetic": "exact integers/Fractions",
"spectrum": check_spectrum(),
"separable_channels": check_separable_channels(),
"scalar_completion": check_scalar_completion(),
"bounded_fourier_completion": check_bounded_fourier_completion(),
"scope": "Finite checks support proofs; no priority or physical-sensor optimality claim."}
if __name__ == '__main__':
print(json.dumps(run(), indent=2, sort_keys=True))