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48 results for Smooth isotopy

Improved proofs for topological and smooth pseudo-isotopies of simply connected 4-manifolds.

problem Proving topological and smooth pseudo-isotopies of simply connected 4-manifolds.
method Provided different arguments that bypass the replacement criterion, thus completing Quinn's proofs.
result Corrected and completed Quinn's proofs of both topological and stable smooth pseudo-isotopy theorems.

We present a grid diagram analogue of Carter, Rieger and Saito's smooth movie theorem. Specifically, we give definitions for grid movies, grid movie isotopies and present a definition of grid planar isotopy as a particular subset of the grid diagram moves: stabilization, destabilization and commutation. We show that gr…

2013-03-07abs ↗pdf ↗

The symplectic isotopy conjecture states that every smooth symplectic surface in CP2CP^2 is symplectically isotopic to a complex algebraic curve. Progress began with Gromov's pseudoholomorphic curves [Gro85], and progressed further culminating in Siebert and Tian's proof of the conjecture up to degree 17 [ST05], but fur…

2017-09-08abs ↗pdf ↗

Smoothly isotopic surfaces in a 4-manifold are stable isotopic if trivial in the 2-homology.

problem Investigating whether topologically isotopic surfaces are smoothly isotopic in stabilised 4-manifolds.
method Analyzing the triviality of surfaces in the 2-homology of the ambient 4-manifold and constructing stabilisations.
result The result holds for surfaces trivial in the 2-homology of the 4-manifold and for certain fundamental groups.

If a continuous map f: X->Q is approximable arbitrary closely by embeddings X->Q, can some embedding be taken onto f by a pseudo-isotopy? This question, called Isotopic Realization Problem, was raised by Shchepin and Akhmet'ev. We consider the case where X is a compact n-polyhedron, Q a PL m-manifold and show that the …

2001-01-05abs ↗pdf ↗

Study on topological pseudo-isotopies of 4-manifolds, proving some cases and finding counterexamples.

problem Determining when a topologically pseudo-isotopic diffeomorphism is also smoothly pseudo-isotopic.
method Analyzing the fundamental group of 4-manifolds and constructing counterexamples.
result Some fundamental groups guarantee a positive answer, while others can have negative outcomes.

David Gabai recently proved a smooth 4-dimensional "Light Bulb Theorem" in the absence of 2-torsion in the fundamental group. We extend his result to 4-manifolds with arbitrary fundamental group by showing that an invariant of Mike Freedman and Frank Quinn gives the complete obstruction to "homotopy implies isotopy" fo…

2019-04-28abs ↗pdf ↗

We develop a new approach to the classical problem on isotopy classification of embeddings of manifolds into Euclidean spaces. This approach involves studying of a new embedding invariant, of almost-embeddings and of smoothing, as well as explicit constructions of embeddings. Using this approach we obtain complete conc…

2006-07-18abs ↗pdf ↗

Generalizing Milnor's result that an FTC (finite total curvature) knot has an isotopic inscribed polygon, we show that any two nearby knotted FTC graphs are isotopic by a small isotopy. We also show how to obtain sharper constants when the starting curve is smooth. We apply our main theorem to prove a limiting result f…

2006-06-01abs ↗pdf ↗

Study equivariant isotopy in higher dimensions, finding exceptions.

problem Under what conditions are equivariant isotopic diffeomorphisms also equivariantly isotopic?
method Construct an invariant valued in the homology of an infinite cover to distinguish isotopic from equivariantly isotopic diffeomorphisms.
result Many equivariant diffeomorphisms are isotopic but not equivariantly isotopic in higher dimensions.

The paper introduces an inequality to detect when surfaces in 4-manifolds are not smoothly isotopic.

problem Detecting when surfaces in 4-manifolds are not smoothly isotopic.
method An adjunction inequality to distinguish non-isotopic surfaces.
result The minimal genus of a surface isotopic to its image under a diffeomorphism is generally larger.

New method for classifying disk embeddings in 4-manifolds.

problem Classifying smooth isotopy classes of neat embeddings of 2-disks in 4-manifolds.
method Using an invariant going back to Dax, constructing a group structure, and relating to mapping class groups.
result The group structure on isotopy classes of neat embeddings is usually not abelian or finitely generated.

The study finds non-simple isotopy classes of links in 3-manifolds, including Legendrian and pseudo-Legendrian examples.

problem Characterizing isotopy classes of links in 3-manifolds, especially in contact structures.
method Developed theory of links transverse to a nowhere-zero vector field, constructing examples in both Legendrian and pseudo-Legendrian settings.
result Non-simple isotopy classes of links exist, including Legendrian and pseudo-Legendrian examples.

The paper gives topological as well as rigid isotopy classification of smooth irreducible algebraic curves in the real projective 3-space for the case when the degree of the curve is at most six and its genus is at most one.

2016-08-12abs ↗pdf ↗

Symplectic Khovanov homology is an invariant of oriented links defined by Seidel and Smith and conjectured to be isomorphic to Khovanov homology. I define morphisms (up to a global sign ambiguity) between symplectic Khovanov homology groups, corresponding to isotopy classes of smooth link cobordisms in 4D between a fix…

2009-12-27abs ↗pdf ↗

Study mapping class groups of 4-manifolds, proving non-finitely generated and splitting properties.

problem Characterize mapping class groups of 4-manifolds.
method Analyzes intersection lattices, automorphisms, and isotopy classes of diffeomorphisms.
result Proves non-finitely generated and splitting properties of mapping class groups.

In this article, we study the smooth mapping class group of a surface S relative to a given Cantor set, that is the group of isotopy classes of orientation-preserving smooth diffeomorphisms of S which preserve this Cantor set. When the Cantor set is the standard ternary Cantor set, we prove that the subgroup consisting…

2015-06-09abs ↗pdf ↗

Regular neighborhoods of singular submanifolds are isotopic to bundle morphisms.

problem Isotoping regular neighborhoods of singular submanifolds to bundle morphisms.
method Leaf preserving isotopy and homogeneity assumptions on foliations.
result Every leaf preserving diffeomorphism of a regular neighborhood is isotopic to a bundle morphism.

The paper studies exotic diffeomorphisms of 4-manifolds with b_+ = 2.

problem Examining exotic diffeomorphisms in 4-manifolds with a specific topological invariant.
method Utilizes Seiberg-Witten invariants for 1-parameter families of 4-manifolds and a gluing formula for connected sums.
result Proves that the mapping class group of certain 4-manifolds is not finitely generated and surjects to Z^∞.

We construct an enhanced version of knot contact homology, and show that we can deduce from it the group ring of the knot group together with the peripheral subgroup. In particular, it completely determines a knot up to smooth isotopy. The enhancement consists of the (fully noncommutative) Legendrian contact homology a…

2016-06-22abs ↗pdf ↗

Smooth knots can be embedded into a specific Menger continuum.

problem Embedding smooth knots into a specific type of continuum.
method Explicit construction using cubical models and self-similarity of the Menger continuum.
result Every smooth knot can be isotoped into the Menger continuum.

A real 3-manifold is a smooth 3-manifold together with an orientation preserving smooth involution, called a real structure. In this article we study open book decompositions on smooth real 3-manifolds that are compatible with the real structure. We call them real open book decompositions. We show that each real open b…

2012-02-27abs ↗pdf ↗

New algebraic theory classifies symplectic curves in complex projective space.

problem Classifying symplectic curves with specific singularities.
method Developed a novel algebraic theory of positive braids and conjugacy classes in the braid group.
result Established a complete classification of isotopy classes of degree three symplectic curves with AnA_n-singularities.

The paper solves isotopy problems on 4-manifolds and classifies symplectic structures.

problem Isotopy problems on 4-manifolds and uniqueness of symplectic structures.
method Generalization of Dax invariant to embedded closed surfaces, symplectic topology techniques.
result Infinitely many non-isotopic symplectic forms on irrational ruled surfaces.