The paper tackles denoising of function samples modulo 1.
problem Recover smooth estimates of a function's modulo 1 samples from noisy data.
method Formulates and solves a quadratically constrained quadratic program relaxation.
result Demonstrates robustness of the approach to noise.
New method improves credit risk estimation and pricing.
problem Estimating risk measures and CDO tranche prices in credit portfolios.
method Mod-Poisson approximation schemes based on mod-φ convergence.
result The method provides more accurate estimates with less computational time.
Estimates smooth function modulo 1 samples robustly from noisy data.
problem Estimating smooth function modulo 1 samples from noisy mod 1 samples.
method Formulates and solves a smoothness regularized least-squares problem over the unit circle.
result Proves robustness to noise for adversarial, Gaussian, and Bernoulli noise models.
Proves simple type conjecture for mod 2 Seiberg-Witten invariants.
problem Proving simple type conjecture for mod 2 Seiberg-Witten invariants.
method Analyzes cohomology ring conditions to prove simple type for all smooth structures.
result Shows existence of topological 4-manifolds with mod 2 simple type.
Study of quotient groups of mapping class groups by power subgroups.
problem Characterizing quotient groups of mapping class groups by power subgroups.
method Analyzing quotient groups Modgn/Modgn[p] for different values of p and n. result Found infinite normal subgroups and Kähler subgroups in specific quotient groups.
We consider two mod-p central series of the free group given by Stallings and Zassenhaus. Applying these series to definitions of Dennis Johnson's filtration of the mapping class group we obtain two mod-p Johnson filtrations. Further, we adapt the definition of the Johnson homomorphisms to obtain mod-p Johnson homomorp…
Let Mod(S) be the extended mapping class group of a surface S. For S the twice-punctured torus, we show that there exists an isomorphism of finite index subgroups of Mod(S) which is not the restriction of an inner automorphism. For S a torus with at least three punctures, we show that every injection of a finite index …
Handlebody groups are rigid under measure equivalence.
problem Proving handlebody groups are rigid under measure equivalence.
method Proving superrigidity for measure equivalence of handlebody groups.
result Every countable group measure equivalent to handlebody groups is virtually isomorphic to them.
Study develops an interpretable model for early mortality prediction in elderly MODS patients.
problem High mortality risk in elderly patients with MODS, unsatisfactory current scoring systems.
method Used eXtreme Gradient Boosting with SHapley Additive exPlanations on MIMIC-III, eICU-CRD, and PLAGH-S datasets.
result Interpretable model outperforms baseline models and clinical scores in predicting hospital mortality.
This paper introduces a new method to create mod m almost classical links from virtual knots.
problem Creating mod m almost classical links from virtual knots.
method Using knots in S_g × S^1 to construct m-fold coverings.
result A new family of m-fold coverings over virtual knots are mod m almost classical.
Researchers compute mod 2 Seiberg-Witten invariants for spin structures and families.
problem Computing mod 2 Seiberg-Witten invariants for spin structures and families.
method Using Pin(2)-symmetry and localisation in equivariant cohomology, the researchers enhance and compute the invariants.
result The mod 2 Seiberg-Witten invariants are computed for spin structures and families, confirming the simple type conjecture mod 2.
Smooth approximation of integral cycles mod 2 in Riemannian manifolds.
problem Approximating mod 2 integral cycles by smooth submanifolds.
method Approximation of mod 2 integral cycles by smooth submanifolds with controlled singularities.
result Every mod 2 integral cycle can be approximated by a smooth submanifold with a controlled singular set.
In this paper, we construct spines, i.e., $\Mod_g$-equivariant deformation retracts, of the Teichmüller space $\T_g$ of compact Riemann surfaces of genus g. Specifically, we define a $\Mod_g$-stable subspace S of positive codimension and construct an intrinsic $\Mod_g$-equivariant deformation retraction from $\T_g$…
Let Mod_g be the mapping class group of a genus g >= 2 surface. The group Mod_g has virtual cohomological dimension 4g-5. In this note we use a theorem of Broaddus and the combinatorics of chord diagrams to prove that H^{4g-5}(Mod_g; Q) = 0.
A new systolic inequality for mod 2 systoles is established.
problem Bounding the product of mod 2 systoles in Riemannian manifolds.
method Analyzing the product of systoles of dimensions 1 and n-1 in closed manifolds with bounded local geometry.
result A systolic inequality is derived for the product of mod 2 systoles, showing a power-law relationship with volume.
Let Sg be the closed oriented surface of genus g and let Mod(Sg) be the mapping class group. When the genus is at least 3, Mod(Sg) can be generated by torsion elements. We prove the follow results. For g≥4, Mod(Sg) can be generated by 4 torsion elements. Three generators are invo…
We establish a mod 2 index theorem for real vector bundles over 8k+2 dimensional compact pin− manifolds. The analytic index is the reduced η invariant of (twisted) Dirac operators and the topological index is defined through KO-theory. Our main result extends the mod 2 index theorem of Atiyan and Singer to non-o…
Let Mod_{g,b} denote the mapping class group of a surface of genus g with b punctures. Feng Luo asked in a recent preprint if there is a universal upper bound, independent of genus, for the number of torsion elements needed to generate Mod_{g,b}. We answer Luo's question by proving that 3 torsion elements suffice to ge…
We characterize convex cocompact subgroups of mapping class groups that arise as subgroups of specially embedded right-angled Artin groups. That is, if the right-angled Artin group G in Mod(S) satisfies certain conditions that imply G is quasi-isometrically embedded in Mod(S), then a purely pseudo-Anosov subgroup H of …
Paper shows ergodicity and irreducibility of mapping class group boundary representation.
problem Ergodicity and irreducibility of mapping class group boundary representation.
method Statistical hyperbolicity and classical result of Masur generalization.
result Boundary representation of mapping class group is ergodic and irreducible.
Paper constructs cyclic coverings of virtual link diagrams, proving equivalence of certain maps.
problem Constructing and proving equivalence of cyclic coverings of virtual link diagrams.
method Introducing m-fold cyclic covering diagrams and proving their equivalence to original diagrams. result Well-defined map from virtual links to mod m almost classical virtual links. The paper solves the Nielsen realization problem for high degree del Pezzo surfaces.
problem Which finite subgroups of the mapping class group of a del Pezzo surface lift to the diffeomorphism group?
method Classification and partial answers for d≥7, equivariant connected sum for d=6. result Complete classification for d≥7, partial answer for d=6. The paper characterizes finite metacyclic subgroups in mapping class groups of surfaces.
problem Characterizing finite metacyclic subgroups in mapping class groups of surfaces.
method Derives necessary and sufficient conditions for conjugates of torsion elements to generate finite split non-abelian metacyclic subgroups.
result Complete classification of certain finite metacyclic subgroups in Mod(Sg) for g≥3. Study on mod 2 Betti numbers of complex hyperplane arrangements and Milnor fiber homology.
problem Determining mod 2 Betti numbers of complex hyperplane arrangement complements.
method Combining the mod 2 Aomoto complex and the transfer long exact sequence.
result First homology of Milnor fiber has non-trivial 2-torsion for the icosidodecahedral arrangement.
We give a presentation for the baseleaf preserving mapping class group Mod(§) of the punctured solenoid §. The generators for our presentation were introduced previously, and several relations among them were derived. In addition, we show that Mod(§) has no non-trivial central elements. Our main tool is a new com…
We publish a table of primitive finite-type invariants of order less than or equal to six, for knots of ten or fewer crossings. We note certain mod-2 congruences, one of which leads to a chirality criterion in the Alexander polynomial. We state a computational result on mod-2 finite-type invariants of 2-strand string l…
The paper solves conditions for metacyclic actions on surfaces, including upper bounds and subgroup classifications.
problem Conditions for metacyclic actions on surfaces and their properties.
method Derives necessary and sufficient conditions for conjugates of torsion elements to generate finite metacyclic subgroups.
result Complete solution to liftability of periodic mapping classes under finite cyclic covers, including upper bounds and subgroup classifications.
Nonorientable surface mapping class group embeds quasi-isometrically in its orientable cover.
problem Embedding nonorientable surface mapping class group in orientable surface mapping class group.
method Utilized semihyperbolicity of orientable surface mapping class group and orientation double covering properties.
result Injective homomorphism is a quasi-isometric embedding.
A new method using mod n covering improves systolic inequalities.
problem Stable systolic inequalities in Riemannian geometry.
method Mod n covering approach to force nonzero cup products or indices.
result Improved stable two systolic bounds for various manifolds.
New EZ-structure maps mapping class group actions.
problem Mapping class group actions on surfaces.
method Constructing a boundary with minimal, strongly proximal, and topologically free action.
result Boundary acts on mapping class group with desired properties.
Multi-Output Dependence (MOD) learning is a generalization of standard classification problems that allows for multiple outputs that are dependent on each other. A primary issue that arises in the context of MOD learning is that for any given input pattern there can be multiple correct output patterns. This changes the…
Computes cohomology of rank 2 bundles, linking to skew Schur polynomials.
problem Cohomology of rank 2 stable bundles with odd determinant.
method Integral cohomology ring computations using Zagier's methods.
result Computes nilpotency degree of a generator in mod two cohomology.
We give an alternative proof of the mod p vanishing theorem by F.Fang of Seiberg-Witten invariants under a cyclic group action of prime order, and generalize it to the case when b1>0. Although we also use the finite dimensional approximation of the monopole map as well as Fang, our method is rather geometric. Furt…
Nonorientable surfaces in rational 4-manifolds linked to Pontrjagin square.
problem Representing nonorientable Lagrangian surfaces in rational 4-manifolds.
method Using the Pontrjagin square of classes in H2(X;Z2) to determine nonorientable surfaces. result A nonzero class A in H2(X;Z2) is represented by a nonorientable embedded Lagrangian surface if and only if P(A)≡(L)mod4. Study identifies roots of hyperelliptic involutions and braid groups in mapping class groups.
problem Identifying roots of hyperelliptic involutions and braid groups in mapping class groups.
method Analyzes braid groups and mapping class groups on surfaces of genus nk. result Hyperelliptic involutions have infinitely many square and cubic roots.
The paper shows how to generate mapping class groups with specific involutions.
problem Finding the minimum number of involutions needed to generate mapping class groups of surfaces with punctures.
method Analyzing the structure of mapping class groups for different surface properties and puncture counts.
result The number of involutions required to generate the mapping class group varies based on the surface's genus and the number of punctures.
In this article, we determine the function ℓ(Sg,p) such that the right-angled Artin group G(Pm) is embedded in the mapping class group Mod(Sg,p) if and only if m is not more than ℓ(Sg,p). Using this function and Birman--Hilden theory, we prove that Mod(S0,p) is vir…
Let Σg,b denote a closed orientable surface of genus g with b punctures and let Mod(Σg,b) denote its mapping class group. In [Luo] Luo proved that if the genus is at least 3, Mod(Σg,b) is generated by involutions. He also asked if there exists a universal upper bound, indepe…
New results on hypersurfaces show no branch points, improving smoothness.
problem Analyzing area minimising hypersurfaces mod p without branch points.
method General analysis of immersed stable minimal hypersurfaces with alternating orientation.
result Area minimising hypersurfaces mod p do not admit immersed branch points.
The study classifies normal subgroups of mapping class groups of surfaces with Cantor subsets.
problem Understanding the structure of normal subgroups in mapping class groups of surfaces with specific subsets.
method Proves two structure theorems: purity and inertia, characterizing normal subgroups.
result Characterizes finite-type normal subgroups of mapping class groups of surfaces with Cantor subsets.
In this paper, by combining modularity of the Witten genus and the modular forms constructed by Liu and Wang, we establish mod 3 congruence properties of certain twisted signatures of 24 dimensional string manifolds.
We study the action of the mapping class group Mod(S) on the boundary dQ of quasifuchsian space Q. Among other results, Mod(S) is shown to be topologically transitive on the subset C in dQ of manifolds without a conformally compact end. We also prove that any open subset of the character variety X(pi_1(S),SL(2,C)) inte…
Let S be a closed, connected, orientable surface of genus at least 3, C(S) be the complex of curves on S and ModS∗ be the extended mapping class group of S. We prove that a simplicial map, λ:C(S)→C(S), preserves nondisjointness (i.e. if α and β are two vertices in $\…
Study shows area-minimizing submanifolds are mostly smooth except for specific types.
problem Understanding when area-minimizing submanifolds are smooth in mod 2 homology.
method Proved area-minimizing submanifolds are not generically smooth except for geodesics, minimal surfaces, and minimal hypersurfaces.
result Area-minimizing submanifolds are not generically smooth, except for geodesics, minimal surfaces, and minimal hypersurfaces.
Study shows area-minimizing submanifolds are mostly smooth except for geodesics, minimal surfaces, and hypersurfaces.
problem Understanding when area-minimizing submanifolds are smooth in mod 2 homology.
method Proving the mod 2 area-minimizing submanifolds are smooth in specific cases and establishing lower bounds on singular sets.
result Area-minimizing submanifolds are not generically smooth, except for geodesics, minimal surfaces, and minimal hypersurfaces.
The paper studies mapping class groups of 3-manifolds fibered over surfaces.
problem Understanding the structure of mapping class groups of 3-manifolds.
method Examines an exact sequence involving the mapping class groups and relates it to the Birman exact sequence.
result Determines conditions under which the exact sequence splits.
Let Σg,p be a closed oriented surface of genus g≥1 with p punctures. Let Mod(Σg,p) be the mapping class group of Σg,p. Wajnryb proved in [Wa] that for p=0,1 Mod(Σg,p) is generated by two elements. Korkmaz proved in [Ko] that one of these generators can be taken…
The paper extends arithmetic Chern-Simons invariants to real quadratic fields and calculates mod 2 Dijkgraaf-Witten invariants.
problem Calculating arithmetic Dijkgraaf-Witten invariants for real quadratic number fields.
method Using modified étale cohomology groups and fundamental groups, explicit formulas are derived for real quadratic fields.
result Explicit formulas for mod 2 arithmetic Dijkgraaf-Witten invariants for real quadratic fields are provided.