How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
A nonzero pi class on a torus has a primitive embedded pi root
Statement
On the original compact torus leaf, a nonzero Π^j class has a primitive embedded representative with the same Π^j property; its sufficiently short fixed-flow fence is an embedded annulus and each positive boundary bounds an actual embedded disk in its leaf.
Facts & Assumptions
Given: A nonzero limitwise-nullhomotopy class on the chosen side of the original compact torus leaf of the present foliation, represented by a fixed-flow fence, and the short fixed-flow fence loops of a representative.
The in-pair item A no-transversal leaf is a torus via the finite accessibility boundary sum identifies the no-transversal leaf as a torus, and the sibling-pair item lem-finite-chart-surface-normal-forms-supply-jordan-disks-and-torsion-free-groups supplies the torus normal form identifying , the torsion-freeness of surface groups and the surface-Jordan disk in the leaf; the sibling-pair item lem-fixed-transverse-fences-have-a-finite-crossing-word supplies the finite crossing word and the fixed-flow fence data.
The limitwise-nullhomotopy predicate defines a well-defined normal subgroup of the based fundamental group. A nonzero class is a nonidentity element of this subgroup, hence an essential loop in the ordinary leaf fundamental group; the class and its powers are well defined on the chosen side (Limitwise-nullhomotopy predicate descends to a normal subgroup).
The holonomy of a leaf is represented on germs of transverse sections by increasing maps defined near the origin, and an increasing map has no nontrivial finite orbit (The holonomy representation and the holonomy group of a leaf).
The standing assumption is Countable Choice as recorded for this pair (The countable-choice principle used in the foliation pair).
An oriented compact surface homeomorphic to the torus admits a diffeomorphism to the standard smooth torus by a finite smooth-carrier and disk-band construction (Finite C2 surface carriers have smooth normal forms and relative cap approximations).
Proof
Choose a diffeomorphism of with the standard torus by [F5], and use its induced identification . Write the nonzero class as with and primitive, . The smooth straight loop modulo is embedded: if two parameter values in had the same projection, their difference times would be integral, and Bezout's identity would make that difference integral, hence zero. Transfer this loop through the inverse diffeomorphism to obtain an actual embedded regular loop on . A path to the basepoint supplies the based primitive class. The given class equals , so a compact based homotopy and fixed-flow fence transport in [F1] identify the original -fence loops with the -fold loops of the -fence. No smoothness of a topological cell map is used.
Let be the increasing one-sided holonomy of . Since has identity one-sided holonomy (its loops are null on the chosen side by the property), for every sufficiently small positive . An increasing map has no nontrivial finite orbit: if its successive iterates strictly increase and if they strictly decrease, so and the short displaced loops close. Their -fold loops are null by the transported compact homotopy and the property of ; oriented surface fundamental groups are torsion-free, so implies . Hence is a genuine nonzero embedded cycle on the same original leaf and the chosen side.
Use the one fixed transverse flow to construct the fence with . Short compact-leafwise separation for the compact loop gives injectivity of the full annulus: if , flow uniqueness gives , so the separation forces equality of the times and of ; embeddedness of gives and strict positivity of gives . Compact-to-Hausdorff then makes the fence an embedding, every is an embedded null curve in its actual leaf, and the surface-Jordan disk lemma of [F1] applied in the leaf, rather than only in its universal cover, gives an actual embedded disk bounded by ; the spherical-leaf alternative is excluded by the in-pair spherical stability item, ensuring the selected disk is unique. This supplies the embedded Reeb construction input, not a deduction of ambient cap embedding from universal-cover caps, and only finitely many fences and homotopies are used, hence only the standing countable choice from [F4].
Depends on
- Finite C2 surface carriers have smooth normal forms and relative cap approximations
- The countable-choice principle used in the foliation pair
- A no-transversal leaf is a torus via the finite accessibility boundary sum
- Finite surface normal forms, Jordan disks, and torsion control
- Fixed transverse fences and their finite crossing words
- Limitwise-nullhomotopy predicate descends to a normal subgroup
- The holonomy representation and the holonomy group of a leaf
Used by
Dependency tree · two levels
69 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- S. P. Novikov, The Topology of Foliations (complete English translation) (standard reference, not scraped)