pith:WHGUBREO
Some questions on entangled linear orders
Under the continuum hypothesis there exist n-entangled linear orders that are not n+1-entangled for every n.
arxiv:2507.17503 v2 · 2025-07-23 · math.LO · math.CO
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Record completeness
Claims
If CH holds, then for every n > 0 there is an n-entangled linear order which is not (n+1)-entangled; similar conditional existence statements hold for homeomorphic reals with differing entanglement, an entangled Pi1^1 set under V=L, and a 2-entangled non-separable order under diamond.
The background definitions of n-entangled linear order and of the relevant descriptive-set-theoretic complexity classes (Pi1^1) as introduced by Abraham-Shelah and used in the constructions, together with the assumption that the ambient universe satisfies the stated extra axioms (CH, V=L, diamond).
Under CH the authors construct n-entangled linear orders that fail to be (n+1)-entangled, plus homeomorphic reals with differing entanglement, an entangled Pi1^1 set under V=L, and a 2-entangled non-separable order under diamond.
References
Formal links
Receipt and verification
| First computed | 2026-06-24T14:15:51.847609Z |
|---|---|
| Builder | pith-number-builder-2026-05-17-v1 |
| Signature | Pith Ed25519
(pith-v1-2026-05) · public key |
| Schema | pith-number/v1.0 |
Canonical hash
b1cd40c48e1dd74e85d43119352940a141015375902f1273bce03396b9ef8b9e
Aliases
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Verify this Pith Number yourself
curl -sH 'Accept: application/ld+json' https://pith.science/pith/WHGUBREODXLU5BOUGEMTKKKAUF \
| jq -c '.canonical_record' \
| python3 -c "import sys,json,hashlib; b=json.dumps(json.loads(sys.stdin.read()), sort_keys=True, separators=(',',':'), ensure_ascii=False).encode(); print(hashlib.sha256(b).hexdigest())"
# expect: b1cd40c48e1dd74e85d43119352940a141015375902f1273bce03396b9ef8b9e
Canonical record JSON
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