Study calculates rational homology groups of configuration spaces for a Moebius strip and a projective plane.
problem Calculating rational homology groups of configuration spaces for specific topological spaces.
method Explicit calculation of all rational homology groups.
result All rational homology groups of configuration spaces for the Moebius strip and projective plane are determined.
Study on rational projective planes with small index singularities.
problem Existence and classification of rational homology projective planes with small index quotient singularities.
method Topological and smooth obstructions analysis, classification of singularities.
result Classification of quotient singularities for rational homology projective planes with indices up to three.
Study shows no smooth embeddings of rational homology balls into complex projective plane.
problem Embedding rational homology balls into complex projective plane.
method Elementary arguments to prove non-existence of almost complex embeddings.
result No smooth embeddings of rational homology balls into complex projective plane.
Classifies degenerations of complex projective plane with rational singularities.
problem Classifying singularities of complex projective plane.
method Assuming Wahl's conjecture, classifies degenerations using rational homology disk smoothing.
result Classifies surfaces with rational singularities, including new degenerations with non-log canonical singularities.
Smooth but not symplectic embeddings of rational balls in complex projective plane found.
problem Finding smooth embeddings of rational balls in complex projective plane that are not symplectic.
method Infinite family of rational homology balls, lattice embedding obstruction from Donaldson's diagonalisation theorem.
result No two examples may be embedded disjointly.
Study Cremona transformations in weighted projective planes to find rational cuspidal curves and Zariski pairs.
problem Finding rational cuspidal curves and Zariski pairs in weighted projective planes.
method Construct families of curves using Cremona transformations, compute fundamental groups, and use blow-up-down decompositions.
result Discover new examples of rational cuspidal curves and Zariski pairs in weighted projective planes.
Paper proves conditions for rational homology complex projective planes with singularities.
problem Proving conditions for rational homology complex projective planes with singularities.
method Leveraging results from smooth 4-manifolds, including Donaldson diagonalization theorem and Heegaard Floer correction terms.
result Eliminates the possibility of a rational homology complex projective plane with four singularities and identifies families of singularities obstructed by smooth conditions.
Classifies curves up to symplectic isotopy.
problem Classifying rational cuspidal curves up to symplectic isotopy.
method Topological tools, pseudoholomorphic techniques, and birational transformations.
result Classifies rational cuspidal curves of degrees 6 and 7 up to symplectic isotopy.
The article simplifies conditions for dimensions supporting a rational projective plane.
problem Classify dimensions supporting a rational projective plane.
method Simplified Barge-Sullivan rational surgery realization theorem conditions combined with signature equation.
result A single quadratic residue equation determines dimension support.
Study constraints on singular points of rational cuspidal curves using Heegaard Floer theory.
problem Constraints on singular points of rational cuspidal curves.
method Involutive Heegaard Floer homology theory.
result Results do not apply to rational cuspidal curves of even degree.
The study identifies only two rational surfaces with constant scalar curvature Kähler metrics.
problem Finding rational surfaces with constant scalar curvature Kähler metrics.
method Analyzing projective rational surfaces and their Kähler metrics.
result There are only two rational surfaces (projective plane and quadric surface) with constant scalar curvature Kähler metrics.
In this paper, we study the existence of high-dimensional, closed, smooth manifolds whose rational homotopy type resembles that of a projective plane. Applying rational surgery, the problem can be reduced to finding possible Pontryagin numbers satisfying the Hirzebruch signature formula and a set of congruence relation…
Formula conjectured for rational cuspidal curves in projective plane.
problem Counting rational cuspidal curves in projective plane.
method Extending Kontsevich's recursion formula and using geometric input about tangency of curves at nodal points.
result Conjectural formula agrees with earlier computations and extends to rational quartics with E6 singularity.
Solved a conjecture about rational homology projective planes with quotient singularities.
problem A conjecture about rational homology projective planes with quotient singularities.
method Combining Donaldson's diagonalization theorem with a distinguished spin^c structure on the smooth locus.
result Proved that rational homology projective planes with quotient singularities have at most three singular points.
Study Markov staircases in symplectic embeddings of rational homology ellipsoids.
problem Symplectic embeddings of rational homology ellipsoids into the complex projective plane.
method Analysis of almost toric fibrations and Hamiltonian isotopies.
result Existence of an infinite staircase for each Markov triple.
Researchers confirm a 15-vertex triangulation of the quaternionic projective plane is minimal.
problem Prove the quaternionic projective plane has a minimal triangulation with 15 vertices.
method Implemented Gaifullin's algorithm to compute the first rational Pontryagin class of the combinatorial manifold.
result The 15-vertex triangulation is indeed a minimal triangulation of the quaternionic projective plane.
Study contact structures on projective spaces, proving infinite non-isotopic structures.
problem Classify contact structures on projective spaces with specific surgery numbers.
method Detailed analysis of Gompf's Γ-invariant and d_3-invariant of tangential 2-plane fields.
result Infinitely many non-isotopic contact structures on real projective 3-space.
New symplectic caps and embeddings found in complex projective plane.
problem Embeddings of homology balls in complex projective plane.
method Handlebody construction of symplectic caps and embeddings.
result First examples of symplectic handlebody decompositions of a closed symplectic 4-manifold.
Explicit formulas for Hattori-Stong integrability conditions and manifolds' signature properties.
problem Understanding and calculating the signature of stably almost-complex manifolds.
method Combinatorial techniques to derive explicit formulas for Chern class coefficients and signature conditions.
result An evenness condition for the signature of stably almost-complex manifolds in terms of Chern numbers.
The aim of this paper is to consider a possible extension of the Bogomolov--Miyaoka--Yau inequality to differentiable orbifolds. The conjectured extension is related to the Montgomery--Yang problem about circle actions on the 5--sphere and also to the H--cobordism of Seifert fibered 3--manifolds. Related conjectures on…
In this paper we study rational real algebraic knots in RP3. We show that two real algebraic knots of degree ≤5 are rigidly isotopic if and only if their degrees and encomplexed writhes are equal. We also show that any irreducible smooth knot which admits a plane projection with less than or equal to four cro…
The study provides a criterion for fractional-linear integrals of geodesics on surfaces.
problem Existence and classification of fractional-linear integrals for geodesic flows on Riemannian surfaces.
method Criterion and analysis of moduli space of local integrals.
result The moduli space of such local integrals is either the 2D projective plane or finite points.
We establish a twistor correspondence between a cuspidal cubic curve in a complex projective plane, and a co-calibrated homogeneous G2 structure on the seven--dimensional parameter space of such cubics. Imposing the Riemannian reality conditions leads to an explicit co-calibrated G2 structure on SU(2,1)/U(1). …
Smooth 4-manifolds have simple horizontal decompositions.
problem Classifying smooth, closed, orientable 4-manifolds.
method Horizontal handlebody decomposition.
result Simplest horizontal decompositions classify closed 4-manifolds.
The paper adapts differential signatures to algebraic curves under group actions.
problem Equivalence problem for complex plane algebraic curves under group actions.
method Adapting differential signature construction to algebraic curves, using classifying invariants.
result Explicit sets of rational classifying invariants and formulas for signature curve degree.
Let E(1)_p denote the rational elliptic surface with a single multiple fiber f_p of multiplicity p. We construct an infinite family of homologous non-isotopic symplectic tori representing the primitive class [f_p] in E(1)_p when p>1. As a consequence, we get infinitely many non-isotopic symplectic tori in the fiber cla…
The rational cohomology ring of A_3, the moduli space of abelian 3-folds is computed. This is isomorphic to the the rational cohomology ring of the group Sp_3(Z) of 6x6 integral symplectic matrices. The main ingredients in the computation are (1) Looijenga's computation of the rational cohomology ring of M_3, the modul…
Study isotopy of rational cuspidal curves in 4-manifolds.
problem Isotopy of rational cuspidal curves in 4-manifolds.
method Tame symplectic curves, pseudo-holomorphic curves, log pairs, 4-dimensional topology.
result Every rational cuspidal curve is isotopic to a complex curve in degrees up to 5.
In this work we study some problems related with algebraic hypersurfaces invariant by foliations on weighted projective spaces PC(ϖ0,...,ϖn) generalizing some results known for $\p$, as for example: the number of singularities, with multiplicities, contained in the invariant quasi-smo…
Study symplectic forms on manifolds to find Lagrangian pinwheels that can be separated.
problem Determine conditions for symplectic forms to carry disjoint Lagrangian pinwheels.
method Use rational blow-up to analyze Lagrangian pinwheels in symplectic manifolds.
result Conditions for disjunction of Lagrangian pinwheels in specific manifolds.
Classifies 4-manifolds with genus one horizontal handlebody decomposition.
problem Classifying 4-manifolds with specific properties.
method Classification using Euler characteristic and handlebody decomposition.
result Found a large family of rational homology balls that embed into CP2. An unobstructedness theorem is proved for deformations of compact holomorphic Poisson manifolds and applied to a class of examples. These include certain rational surfaces and Hilbert schemes of points on Poisson surfaces. We study in particular the Hilbert schemes of the projective plane and show that a generic deform…
This article shows that every non-isotropic harmonic 2-torus in complex projective space factors through a generalised Jacobi variety related to the spectral curve. Each map is composed of a homomorphism into the variety and a rational map off it. The same ideas allow one to construct (pluri)-harmonic maps of finite ty…
New results on plane graphs linked to rational functions.
problem Existence problems for plane graphs with specific degree conditions.
method Recent results on the Hurwitz existence problem.
result Description of Belyi functions corresponding to such graphs.
In this short note, we present a construction of new symplectic 4-manifolds with non-negative signature using the complex surfaces on Bogomolov-Miyaoka-Yau line c12=9χh, the fake projective planes and Cartwright-Steger surfaces. Our construction yields an infinite family of fake rational homology $(2n-1)\CP#(2n-…
We present an approach of computing the intersection curve C of two rational parametric surface §1(u,s) and §2(v,t), one being projectable and hence can easily be implicitized. Plugging the parametric surface to the implicit surface yields a plane algebraic curve G(v,t)=0. By analyzing the topology …
Study rationality of meromorphic functions between real algebraic sets in the plane.
problem Understanding rationality of meromorphic functions mapping real algebraic sets to complex algebraic sets.
method Using Schwarz reflection functions and theory of meromorphic functions.
result For certain real algebraic sets, meromorphic functions are rational.
We apply the methods of Heegaard Floer homology to identify topological properties of complex curves in the complex projective plane. As one application, we resolve an open conjecture that constrains the Alexander polynomial of the link of the singular point of the curve in the case that there is exactly one singular p…
Projective loops generate rational loop groups without needing nilpotent loops.
problem Generating rational loop groups with noncompact reality conditions.
method Used projective loops to prove rational loop groups can be generated.
result Projective loops alone are sufficient to generate rational loop groups.
The study classifies semiaffine stable planes into affine, projective, or punctured projective planes.
problem Characterizing semiaffine stable planes.
method Analyzing properties of lines and points in stable planes.
result Semiaffine stable planes are either affine, projective, or punctured projective planes.
Using symplectic topology and the Radon transform, we prove that smooth 4-dimensional projective planes are diffeomorphic to CP2. We define the notion of a plane curve in a smooth projective plane, show that plane curves in high dimensional regular planes are lines, prove that homeomorphisms preserving plan…
In this paper we provide a classification of all Moishezon twistor spaces on the connected sum of four complex projective planes. This is given by means of the anticanonical system of the twistor spaces. In particular, we show that the anticanonical map is birational, two to one over the image, or otherwise the image o…
We derive the quantum Teichmüller space, previously constructed by Kashaev and by Fock and Chekhov, from tensor products of a single canonical representation of the modular double of the quantum plane. We show that the quantum dilogarithm function appears naturally in the decomposition of the tensor square, the quantum…
New geometric proof for rational tangles links-quivers correspondence.
problem Recovering symmetric/antisymmetric colored HOMFLY-PT polynomials from a quiver.
method Geometric approach using winding numbers in punctured plane and its second configuration space.
result Explicit description of quivers for rational tangles.
We use reduced homogeneous coordinates to study Riemannian geometry of the octonionic (or Cayley) projective plane. Our method extends to the para-octonionic (or split octonionic) projective plane, the octonionic projective plane of indefinite signature, and the hyperbolic dual of the octonionic projective plane; we di…
Study projective structures and rational curves to understand Painlevé equations.
problem Analyzing projective structures and rational curves on surfaces.
method Analytic classification, normal forms, pencil/fibration decomposition, infinitesimal symmetries.
result Deduced transcendental results about Painlevé equations.
Study trisections on rational elliptic surfaces to find new Zariski pairs.
problem Constructing trisections and related plane curves on rational elliptic surfaces.
method Utilized Mumford representations of semi-reduced divisors to construct trisections and plane curves.
result Existence of a family of Zariski pairs degenerating to the same conic-line arrangement.
Survey on minimal rational curves and their geometric structures.
problem Germ-equivalence problem of minimal rational curves on uniruled projective manifolds.
method Analysis of isotrivial families of projective varieties and G-structures.
result Natural G-structure on Zariski-open subset of uniruled projective manifolds.