Study genus-three Torelli maps and their fixed point sets in representation varieties.
problem Understanding fixed point sets and representation varieties of genus-three Torelli maps.
method Analyzing fixed point sets and representation varieties of powers of bounding pair maps.
result Determined the number of connected components of fixed point sets and representation varieties.
Study on mapping class groups for low genus surfaces.
problem Arithmetic image of homological representations for low genus mapping class groups.
method Examined centralizers of finite groups acting on surfaces with genus at most 3.
result Complete answer to the arithmetic image question for low genus surfaces.
The study explores SU(2) representations in 3-manifolds and knots with specific Heegaard genus constraints.
problem Characterizing SU(2) representations in 3-manifolds and knots based on their Heegaard genus and homology properties.
method Analyzes the homology groups and Heegaard genus of 3-manifolds and knots to find representations.
result Identifies conditions under which specific SU(2) and SO(3) representations exist.
Researchers create projective representations of Hecke groups using TQFT.
problem Constructing projective representations of Hecke groups.
method Using Witten-Reshetikhin-Turaev topological quantum field theory of higher genus surfaces.
result The representation's image group is infinite at low levels in genus 2.
Researchers compute cohomology of mapping class groups with Prym representations, showing instability for large genus.
problem Computing the cohomology of mapping class groups with level structures and Prym representations.
method Using twisted cohomology and Prym representations for any positive integer r.
result Cohomology exhibits instability for large genus, but remains stable for r=0 or r=1.
Classifies finite orbits of mapping class group actions on surface group representations.
problem Finite orbits of mapping class group actions on surface group representations.
method Classification based on surface genus and representation properties.
result Finite orbits correspond to homomorphisms with finite image for genus at least two, and to finite or special dihedral representations for genus one.
New lower bound for knot genus using Links-Gould invariant.
problem Finding a tighter lower bound for knot genus.
method Representation theory of Uqgl(2∣1) to prove degree of Links-Gould polynomial bounds Seifert genus. result The Links-Gould polynomial provides a new lower bound on knot genus, detecting specific knots like Kinoshita-Terasaka and Conway.
Nonorientable surfaces have a faithful linear representation of a specific dimension.
problem Understanding the structure of hyperelliptic mapping class groups of nonorientable surfaces.
method Proved the existence of a faithful linear representation of dimension g2−1. result The hyperelliptic mapping class group of a nonorientable surface of genus g≥4 has a faithful representation into GL(g2−1,R). A realization of a virtual link diagram is obtained by choosing over/under markings for each virtual crossing. Any realization can also be obtained from some representation of the virtual link. (A representation of a virtual link is a link diagram on an oriented 2-dimensional surface.) We prove that if a minimal genus …
Study of low dimensional representations of mapping class groups of surfaces, focusing on genus ≥ 7.
problem Classifying (2g+1)-dimensional complex linear representations of mapping class groups. method Using twisted 1-cohomology groups and Morita's computation, a complete classification is given for g≥7. result No irreducible linear representations of dimension 2g+1 for g≥7. The paper studies representations of surface groups into PSL(2,R) and their geometric realizations.
problem Investigating representations of surface groups into PSL(2,R) and their geometric realizations.
method Analyzing hyperbolic cone-structures on surfaces and their relationship with representations.
result Every almost extremal representation of a surface group into PSL(2,R) arises as the holonomy of a hyperbolic cone-structure.
We construct integral bases for the SO(3)-TQFT-modules of surfaces in genus one and two at roots of unity of prime order and show that the corresponding mapping class group representations preserve a unimodular Hermitian form over a ring of algebraic integers. For higher genus surfaces the Hermitian form sometimes must…
We prove that the sequence of projective representations of the mapping class group obtained from the projective flat connection in the SU(n)-Verlinde bundles over Teichmuller space is asymptotically faithful, that is the intersection over all levels of the kernels of these representations is trivial, whenever the genu…
The Frey--Mazur conjecture states that an elliptic curve over Q is determined up to isogeny by its p-torsion Galois representation for p≥17. We study a geometric analog of this conjecture, and show that the map from isogeny classes of "fake elliptic curves"---abelian surfaces with quaternionic multip…
New polynomial connects knot genus to 3-manifold geometry.
problem Detecting knot genus from 3-manifold geometry.
method Ideal triangulation and super-Ptolemy assignments.
result New polynomial conjecturally agrees with torsion polynomial.
New knots with specific properties have larger 4-genus than previously known bounds.
problem Finding knots with large 4-genus values.
method Constructing 2-solvable and 2-bipolar knots using specific representations and signatures.
result Knots have 4-genus greater than any given integer g.
Researchers create coordinates for hyperbolic surfaces, proving a magic formula.
problem Constructing coordinates for hyperbolic structures on genus-2 surfaces.
method Developed Fenchel-Nielsen coordinates and Wolpert's magic formula analogues.
result Found Darboux charts for the Goldman symplectic form on branched hyperbolic structures.
Paper uses harmonic surfaces to model surfaces of any complexity.
problem Topological limitations of minimal surfaces restrict their use.
method Weierstrass representation for harmonic surfaces to construct arbitrary genus surfaces.
result Harmonic surfaces can be used to create surfaces of arbitrary genus.
Improved lower bounds for faithful linear representations of mapping class groups.
problem Finding the minimum dimension of faithful linear representations of mapping class groups.
method Using finer study of commutation relations and specific pants decompositions to show representations must kill certain subgroups.
result Established lower bounds of 4g−3 for faithful representations of mapping class groups of genus g≥7. Study calculates Alexander polynomials for a specific knot type.
problem Determining knot properties like genus and fiberedness.
method Calculates twisted Alexander polynomials for (−2,3,2n+1)-pretzel knots. result Supports Dunfield, Friedl, and Jackson's conjecture.
Quantum representations of mapping class groups are locally rigid at prime levels.
problem Locally rigid properties of quantum representations of mapping class groups.
method Proving local rigidity for Fibonacci representations of mapping class groups at prime levels.
result Local rigidity of Fibonacci representations of mapping class groups at prime levels.
Classifies representations up to dimension 3g-3 for surface mapping class groups.
problem Classifying representations of mapping class groups up to a certain dimension.
method Direct sum of a 2g or 2g+1 dimensional representation and a trivial one.
result Any representation up to dimension 3g-3 is a direct sum of a 2g or 2g+1 dimensional representation and a trivial one.
Paper constructs a minimal surface with specific ends and curvature.
problem Constructing a minimal surface with specific topological and geometric properties.
method Weierstrass representation, elliptic functions, and solving the period problem.
result Existence of a complete immersed minimal surface of genus one with specified ends and total Gauss curvature.
In this paper we construct a faithful representation of the mapping class group of the genus two surface into a group of matrices over the complex numbers. Our starting point is the Lawrence-Krammer representation of the braid group B_n, which was shown to be faithful by Bigelow and Krammer. We obtain a faithful repres…
Chart descriptions are a graphic method to describe monodromy representations of various topological objects. Here we introduce a chart description for genus-two Lefschetz fibrations, and show that any genus-two Lefschetz fibration can be stabilized by fiber-sum with certain basic Lefschetz fibrations.
We decompose into irreducible factors the SU(2) Witten-Reshetikhin-Turaev representations of the mapping class group of a genus 2 surface when the level is p=4r and p=2r2 with r an odd prime and when p=2r1r2 with r1, r2 two distinct odd primes. Some partial generalizations in higher genus are…
Characterizes area-minimizing maps for surfaces of genus ≥ 2.
problem Equivariant area-minimizing maps on surface covers.
method Classifies minimal surfaces in Hilbert spheres with constant negative Gaussian curvature.
result Characterizes all equivariantly area-minimizing maps from the universal cover of a surface to a Hilbert sphere.
We show the triviality of representations of the mapping class group of a genus g surface in GL(n,C),Diff(S2) and Homeo(T2) when appropriate restrictions on the genus g and the size of n hold. For example, if Sg is a surface of finite type and φ:MCG(Sg)→GL(n,C) is a homomorphism, then φ is tri…
The study examines modular fusion categories with trivial Torelli group actions.
problem Characterizing modular fusion categories with trivial Torelli group actions.
method Analyzing the mapping class group representations and their kernels.
result For modular fusion categories, the Torelli group is contained in the kernel of the genus-g representation if and only if the category is pointed. A well-known conjecture asserts that the mapping class group of a surface (possibly with punctures/boundary) does not virtually surject onto Z if the genus of the surface is large. We prove that if this conjecture holds for some genus, then it also holds for all larger genera. We also prove that if there is a counte…
Researchers study Prym representations for handlebody groups, focusing on cyclic cases.
problem Understanding Prym representations for handlebody groups and their images.
method Restrict Prym representations to handlebody groups and twist groups, focusing on cyclic cases.
result Determined the image of Prym representations in the cyclic case for handlebody groups.
Bounds on knot polynomials for Lie superalgebras of type I.
problem Determining genus bounds for knot polynomials colored by Lie superalgebra representations.
method Proved bounds on the t-degree of knot polynomials, relating it to the number of odd roots and the genus of the knot. result Proved bounds on knot polynomials for Lie superalgebras of type I, showing equality for certain knots.
The study examines dynamics on SU(2)-representation varieties for surfaces and non-orientable surfaces.
problem Dynamics of group actions on SU(2)-representation varieties of surfaces and non-orientable surfaces.
method Description and analysis of group actions generated by Dehn twists on SU(2)-representation varieties.
result Explicit invariant rational functions on SU(2)-representation varieties for specific cases of surfaces and non-orientable surfaces.
Formula for colored Links-Gould polynomial with genus bounds.
problem Calculating polynomial for knots colored with specific representations.
method Cabling formula and genus bounds for the Links-Gould polynomial.
result Genus bounds and specialization to Alexander polynomial for colored Links-Gould polynomial.
Proof that SU(2) character variety of genus 2 surface is CP3.
problem Character variety structure of genus 2 surface.
method Differential topology, algebraic topology, SU(2) representations. result Character variety is homeomorphic to CP3. Morifuji computed the twisted Alexander polynomial of twist knots for nonabelian representations. In this paper we compute the twisted Alexander polynomial and the Reidemeister torsion of genus one two-bridge knots, a class of knots which includes twist knots. As an application, we give a formula for the Reidemeister t…
Let e denote the Euler class on the space Hom(Γg,PSL(2,R)) of representations of the fundamental group Γg of the closed surface Σg of genus g. Goldman showed that the connected components of Hom(Γg,PSL(2,R)) are precisely the inverse images e−1(k), for 2−2g≤k≤2g−2, and t…
The SU(2) TQFT representation of the mapping class group of a closed surface of genus g, at a root of unity of prime order, is shown to be irreducible. Some examples of reducible representations are also given.
We prove that the image of the mapping class group by the representations arising in the SU(2)-TQFT is infinite, provided that the genus is bigger than 2 and the level r of the theory is different from 2,3,4,6. In particular the quotient of the mapping class group by the normaizer of the r-th power of a Dehn twist is i…
We give new explicit formulas for the representations of the mapping class group of a genus one surface with one boundary component which arise from Integral TQFT. Our formulas allow one to compute the h-adic expansion of the TQFT-matrix associated to a mapping class in a straightforward way. Truncating the h-adic expa…
In the genus expansion of the HOMFLY polynomials their representation dependence is naturally captured by symmetric group characters. This immediately implies that the Ooguri-Vafa partition function (OVPF) is a Hurwitz tau-function. In the planar limit involving factorizable special polynomials, it is actually a trivia…
Study on kernels of SO(3) WRT representations for surfaces of genus g≥3.
problem Determine if the kernel of SO(3) WRT representations is generated by p-th powers of Dehn twists.
method Investigate kernels for different genus and prime p values, showing containment in specific subgroups.
result Kernels are contained in subgroups generated by p-th powers of Dehn twists and other specific elements for certain conditions.
Braid groups help create complex surfaces in algebraic geometry.
problem Creating projective surfaces defined over complex numbers.
method Representation theory of higher genus braid groups.
result Interesting examples of projective surfaces produced.
Study knot invariants to answer questions about slice genus and clasp numbers.
problem Whether the difference between the four-dimensional clasp number and the slice genus can be arbitrarily large.
method Equivariant singular instanton theory and Chern--Simons functional.
result Answers a conjecture by Livingston about slicing numbers and provides a lower bound for the unoriented slice genus.
For large genus, precise monodromy groups are calculated for surface covers.
problem Calculating precise monodromy groups for large genus surface covers.
method Hodge-theoretic methods, including a generic Torelli theorem with coefficients.
result Precise connected monodromy groups are calculated for large genus surface covers.
We use geometric techniques to explicitly find the topological structure of the space of SO(3)-representations of the fundamental group of a closed surface of genus 2 quotient by the conjugation action by SO(3). There are two components of the space. We will describe the topology of both components and describe the cor…
In the planar limit of the 't Hooft expansion, the Wilson-loop average in 3d Chern-Simons theory (i.e. the HOMFLY polynomial) depends in a very simple way on representation (the Young diagram), so that the (knot-dependent) Ooguri-Vafa partition function becomes a trivial KP tau-function. We study higher genus correctio…
Investigates minimal genus of second homology classes in RAAGs, finding bounds and specific cases.
problem Minimal genus of second homology classes in right angled Artin groups.
method Lower bounds, characterizations, and examples to show minimal genus.
result Minimal genus is half the rank for complete graphs, trees, and complete bipartite graphs, and can be realized by disjoint unions of tori.