Symplectic 𝐒¹×𝐍³, subgroup separability, and vanishing Thurston norm
Bibliographic record
Abstract
Let N N be a closed, oriented 3 3 –manifold. A folklore conjecture states that S 1 × N S^{1} \times N admits a symplectic structure if and only if N N admits a fibration over the circle. We will prove this conjecture in the case when N N is irreducible and its fundamental group satisfies appropriate subgroup separability conditions. This statement includes 3 3 –manifolds with vanishing Thurston norm, graph manifolds and 3 3 –manifolds with surface subgroup separability (a condition satisfied conjecturally by all hyperbolic 3 3 –manifolds). Our result covers, in particular, the case of 0 0 –framed surgeries along knots of genus one. The statement follows from the proof that twisted Alexander polynomials decide fiberability for all the 3 3 –manifolds listed above. As a corollary, it follows that twisted Alexander polynomials decide if a knot of genus one is fibered.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.003 |
| Scholarly communication | 0.002 | 0.004 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.011 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".