Bar-Natan's Khovanov homology for coloured links

Ribbon distance bounds from Bar-Natan Homology and $α$-Homology

We prove a lower bound on the ribbon distance via Bar-Natan Homology. This lower bound agrees with Alishahi's lower bound on the unknotting number via Bar-Natan Homology, which furthers a pattern first observed by Sarkar: Sarkar's lower bound on the ribbon distance via Lee Homology agreed with Alishahi and Dowlin's lower bound on the unknotting number via Lee Homology. We also prove a lower bound on the ribbon distance via $α$-homology, a variant of Khovanov homology defined recently by Khovanov and Robert.

Instantons and Bar-Natan homology

A spectral sequence is established, whose $E_{2}$ page is Bar-Natan's variant of Khovanov homology and which abuts to a deformation of instanton homology for knots and links. This spectral sequence arises as a specialization of a spectral sequence whose $E_{2}$ page is a characteristic-2 version of $F_{5}$ homology, in Khovanov's classification.

Immersed curves in Khovanov homology

We give a geometric interpretation of Bar-Natan's universal invariant for the class of tangles in the 3-ball with four ends: we associate with such 4-ended tangles $T$ multicurves $\widetilde{\operatorname{BN}}(T)$, that is, collections of immersed curves with local systems in the 4-punctured sphere. These multicurves are tangle invariants up to homotopy of the underlying curves and equivalence of the local systems. They satisfy a gluing theorem which recovers the reduced Bar-Natan homology of links in terms of wrapped Lagrangian Floer theory. Furthermore, we use $\widetilde{\operatorname{BN}}…

Reduced 2-coloured Khovanov Homology detects the Trefoil

We prove that the reduced 2-coloured Khovanov homology detects the trefoil, using a spectral sequence to knot Floer homology.

Khovanov同调札记

Notes on Khovanov homology

本文是一份研究生专题课程讲义，系统介绍Khovanov同调及其相关不变量，涵盖Jones多项式、Bar-Natan配边范畴、谱序列、稳定同伦型和skein lasagna模等主题。

Open-closed TQFTs extend Khovanov homology from links to tangles

We use a special kind of 2-dimensional extended Topological Quantum Field Theories (TQFTs), so-called open-closed TQFTs, in order to extend Khovanov homology from links to arbitrary tangles, not necessarily even. For every plane diagram of an oriented tangle, we construct a chain complex whose homology is invariant under Reidemeister moves. The terms of this chain complex are modules of a suitable algebra A such that there is one action of A or A^op for every boundary point of the tangle. We give examples of such algebras A for which our tangle homology theory reduces to the link homology theo…

The Bar-Natan homology and unknotting number

We show that the order of torsion homology classes in Bar-Natan deformation of Khovanov homology is a lower bound for the unknotting number. We give examples of knots that this is a better lower bound than |s(K)/2|, where s(K) is the Rasmussen s invariant defined by the Bar-Natan spectral sequence.

带色Khovanov-Rozansky同调的对称性

Symmetries of colored Khovanov-Rozansky homology

该研究在带色$\frak{gl}_N$-Khovanov-Rozansky同调上构造Witt代数正半部分的作用，证明其与带色链环同调的函子性相容，借助Bar-Natan的范畴框架在缠结层面完成相关命题的证明。

关于3-辫的Khovanov同调

On the Khovanov homology of 3-braids

本研究证明了3股辫闭包的Khovanov同调仅含2阶挠元的Przytycki-Sazdanovic猜想，补全了3-辫Murasugi分类中剩余一类的证明，同时验证了Knight移动猜想对3-辫成立。

Instantons, Bar-Natan homology, and some concordance invariants of knots

A spectral sequence is established, from Bar-Natan's variant of Khovanov homology to a deformation of instanton homology for knots and links. This spectral sequence arises as a specialization of a spectral sequence from a characteristic-2 version of $F_5$ homology, in Khovanov'sclassification. Concordance invariants of knots are derived from the corresponding instanton homology groups, including a 1-parameter family of homomorphisms $f_r$ from the concordance group to the reals, having the potential to provide independent bounds on the genus and number of double points for immersed surfaces wi…

Homology of coloured posets: a generalisation of Khovanov's cube construction

We define a homology theory for a certain class of posets equipped with a representation. We show that when restricted to Boolean lattices this homology is isomorphic to the homology of the "cube" complex defined by Khovanov.

Fixing the functoriality of Khovanov homology

We describe a modification of Khovanov homology (math.QA/9908171), in the spirit of Bar-Natan (math.GT/0410495), which makes the theory properly functorial with respect to link cobordisms. This requires introducing `disorientations' in the category of smoothings and abstract cobordisms between them used in Bar-Natan's definition. Disorientations have `seams' separating oppositely oriented regions, coming with a preferred normal direction. The seams satisfy certain relations (just as the underlying cobordisms satisfy relations such as the neck cutting relation). We construct explicit chain maps…

Odd annular Bar-Natan category and gl(1|1)

We introduce two monoidal supercategories: the odd dotted Temperley-Lieb category $\mathcal{T\!L}_{o,\bullet}(δ)$, which is a generalization of the odd Temperley-Lieb category studied by Brundan and Ellis, and the odd annular Bar-Natan category $\mathcal{BN}_{\!o}(\mathbb{A})$, which generalizes the odd Bar-Natan category studied by Putyra. We then show there is an equivalence of categories between them if $δ=0$. We use this equivalence to better understand the action of the Lie superalgebra $\mathfrak{gl}(1|1)$ on the odd Khovanov homology of a knot in a thickened annulus found by Grigsby and…

用于Khovanov同调的离散Morse理论

Discrete Morse Theory for Khovanov Homology

本文将离散Morse理论引入纽结同调领域，应用于Bar-Natan带点配边范畴中的2、3环面辫子，得到相关链环整系数Khovanov同调的归纳结果，推进了3辫子闭合Khovanov同调仅含2挠的猜想研究。

Bundles of coloured posets and a Leray-Serre spectral sequence for Khovanov homology

The decorated hypercube found in the construction of Khovanov homology for links is an example of a Boolean lattice equipped with a presheaf of modules. One can place this in a wider setting as an example of a coloured poset, that is to say a poset with a unique maximal element equipped with a presheaf of modules. In this paper we initiate the study of a bundle theory for coloured posets, producing for a certain class of base posets a Leray-Serre type spectral sequence. We then show how this theory finds application in Khovanov homology by producing a new spectral sequence converging to the Kh…

A perturbation of the geometric spectral sequence in Khovanov homology

We study the relationship between Bar-Natan's perturbation in Khovanov homology and Szabo's geometric spectral sequence, and construct a link invariant that generalizes both into a common theory. We study a few properties of the new invariant, and introduce a family of s-invariants from the new theory in the same spirit as Rasmussen's s-invariant.

A Kirby color for Khovanov homology

We construct a Kirby color in the setting of Khovanov homology: an ind-object of the annular Bar-Natan category that is equipped with a natural handle slide isomorphism. Using functoriality and cabling properties of Khovanov homology, we define a Kirby-colored Khovanov homology that is invariant under the handle slide Kirby move, up to isomorphism. Via the Manolescu--Neithalath 2-handle formula, Kirby-colored Khovanov homology agrees with the $\mathfrak{gl}_{2}$ skein lasagna module, hence is an invariant of $4$-dimensional $2$-handlebodies.

论 Bar-Natan–van der Veen 的扰动高斯多项式

On Bar-Natan - van der Veen's perturbed Gaussians

本文研究 Bar-Natan–van der Veen 基于非交换高斯演算提出的多项式时间纽结多项式族，证明其中半数为零，给出三个不变量的具体公式，并分析其在连通和下的行为。

An Introduction to Khovanov Homology

This paper is an introduction to Khovanov homology, starting with the Kauffman bracket state summation, emphasizing the Bar-Natan Canopoloy and tangle cobordism approach. The paper discusses a simplicial approach to Khovanov homology and a quantum model for it so that the graded Euler characteristic that produces the Jones polynomial from Khovanov homology becomes the trace of a unitary transformation on a Hilbert space associated with the Khovanov Homology.

Khovanov homology in characteristic two and involutive monopole Floer homology

We study the conjugation involution in Seiberg-Witten theory in the context of the Ozsváth-Szabó and Bloom's spectral sequence for the branched double cover of a link $L$ in $S^3$. We prove that there exists a spectral sequence of $\mathbb{F}[Q]/Q^2$-modules (where $Q$ has degree $-1$) which converges to $\widetilde{\mathit{HMI}}_*(Σ(L))$, an involutive version of the monopole Floer homology of the branched double cover, and whose $E^2$-page is a version of Bar Natan's characteristic two Khovanov homology of the mirror of $L$. We conjecture that an analogous result holds in the setting of $\ma…

The Bar-Natan skein module of the solid torus and the homology of (n,n) Springer varieties

This paper establishes an isomorphism between the Bar-Natan skein module of the solid torus with a particular boundary curve system and the homology of the (n,n) Springer variety. The results build on Khovanov's work with crossingless matchings and the cohomology of the (n,n) Springer variety. We also give a formula for comultiplication in the Bar-Natan skein module for this specific three-manifold and boundary curve system.

A cobordism realizing crossing change on $\mathfrak{sl}_2$ tangle homology and a categorified Vassiliev skein relation

In this paper, we discuss degree 0 crossing change on Khovanov homology in terms of cobordisms. Namely, using Bar-Natan's formalism of Khovanov homology, we introduce a sum of cobordisms that yields a morphism on complexes of two diagrams of crossing change, which we call the "genus-one morphism." It is proved that the morphism is invariant under the moves of double points in tangle diagrams. As a consequence, in the spirit of Vassiliev theory, taking iterated mapping cones, we obtain an invariant for singular tangles that extending sl(2) tangle homology; examples include Lee homology, Bar-Nat…

Khovanov homology and periodic links

Based on the results of the second author, we define an equivariant version of Lee and Bar-Natan homology for periodic links and show that there exists an equivariant spectral sequence from the equivariant Khovanov homology to equivariant Lee homology. As a result we obtain new obstructions for a link to be periodic. These obstructions generalize previous results of Przytycki and of the second author.

A scanning algorithm for odd Khovanov homology

We adapt Bar-Natan's scanning algorithm for fast computations in (even) Khovanov homology to odd Khovanov homology. We use a mapping cone construction instead of a tensor product, which allows us to deal efficiently with the more complicated sign assignments in the odd theory. The algorithm has been implemented in a computer program. We also use the algorithm to determine the odd Khovanov homology of 3-strand torus links.

等变Khovanov同调中不可定向曲面的混合不变量

A mixed invariant of non-orientable surfaces in equivariant Khovanov homology

本文通过Lee和Bar-Natan形变构造不可定向曲面的混合不变量，用于区分同一纽结界定的不同曲面，并成功处理了若干奇异例子。

4股环面链环的Morse匹配与Khovanov同调

Morse matchings and Khovanov homology of 4-strand torus links

本文提出一种推迟消去的Morse理论简化算法用于计算Khovanov同调，并借此完整计算了4股环面链环的整系数Khovanov同调群，发现大量4-挠元，验证了极限情形下的相关猜想并给出有理Gordian距离下界。

Strong Khovanov-Floer Theories and Functoriality

We provide a unified framework for proving Reidemeister-invariance and functoriality for a wide range of link homology theories. These include Lee homology, Heegaard Floer homology of branched double covers, singular instanton homology, and \Szabo's geometric link homology theory. We follow Baldwin, Hedden, and Lobb (arXiv:1509.04691) in leveraging the relationships between these theories and Khovanov homology. We obtain stronger functoriality results by avoiding spectral sequences and instead showing that each theory factors through Bar-Natan's cobordism-theoretic link homology theory.

\u211dP³中零同调链环的Bar-Natan同调

Bar-Natan Homology for null homologous links in \mathbb{RP}^3

本文在二元域上为\u211dP³中零同调链环引入Bar-Natan同调（Khovanov同调的形变），定义s不变量并证明亏格界，关键为扭曲定向概念。

Virtual Khovanov homology using cobordisms

We extend Bar-Natan's cobordism based categorification of the Jones polynomial to virtual links. Our topological complex allows a direct extension of the classical Khovanov complex ($h=t=0$), the variant of Lee ($h=0,t=1$) and other classical link homologies. We show that our construction allows, over rings of characteristic two, extensions with no classical analogon, e.g. Bar-Natan's $\mathbb{Z}/2$-link homology can be extended in two non-equivalent ways. Our construction is computable in the sense that one can write a computer program to perform calculations, e.g. we have written a Mathemati…

Jones-Wenzl投影算子与奇Khovanov同调

Jones-Wenzl projectors and odd Khovanov homology

本文用分次多范畴推广了Temperley-Lieb代数的奇Khovanov同调范畴化，证明了奇Khovanov同调中范畴化Jones-Wenzl投影算子的存在性与唯一性，并由此导出彩色琼斯多项式的新“奇”范畴化。

On transverse invariants from Khovanov homology

O. Plamenevskaya associated to each transverse knot K an element of the Khovanov homology of K. In this paper, we give two refinements of Plamenevskaya's invariant, one valued in Bar-Natan's deformation of the Khovanov complex and another as a cohomotopy element of the Khovanov spectrum. We show that the first of these refinements is invariant under negative flypes and SZ moves; this implies that Plamenevskaya's class is also invariant under these moves. We go on to show that for small-crossing transverse knots K, both refinements are determined by the classical invariants of K.

On Khovanov Homology and Related Invariants

This paper begins with a survey of some applications of Khovanov homology to low-dimensional topology, with an eye toward extending these results to $\mathfrak{sl}(n)$ homologies. We extend Levine and Zemke's ribbon concordance obstruction from Khovanov homology to $\mathfrak{sl}(n)$ homology for $n \geq 2$, including the universal $\mathfrak{sl}(2)$ and $\mathfrak{sl}(3)$ homology theories. Inspired by Alishahi and Dowlin's bounds for the unknotting number coming from Khovanov homology and relying on spectral sequence arguments, we produce bounds on the alternation number of a knot. Lee and B…

Bar-Natan 绞合 lasagna 模与 4 维流形中的奇异曲面

Bar-Natan skein lasagna modules and exotic surfaces in 4-manifolds

本文利用 Bar-Natan Khovanov 同调构造绞合 lasagna 模，并通过连通和粘合映射在 4 维流形中生成带边界的奇异曲面，证明一次内部稳定化通常不足以消除其奇异性。

Functoriality for the su(3) Khovanov homology

We prove that Morrison and Nieh's categorification of the su(3) quantum knot invariant is functorial with respect to tangle cobordisms. This is in contrast to the categorified su(2) theory, which was not functorial as originally defined. We use methods of Bar-Natan to construct explicit chain maps for each variation of the third Reidemeister move. Then, to show functoriality, we modify arguments used by Clark, Morrison, and Walker to show that induced chain maps are invariant under Carter and Saito's movie moves.

关于链环同调与打结曲面的讲义

Lecture notes on link homologies and knotted surfaces

本文基于2024年Georgia拓扑暑期学校讲义，介绍链环同调理论如何通过配边同态研究四维空间中的打结曲面，并重点讲解Khovanov同调、Bar-Natan同调的计算技术及Bar-Natan范畴的作用。

A cobordism category attached to Khovanov-Rozansky link homologies based on operads

We consider colored operads and their actions on categories. As a special example we construct a cobordism category with a colored operad action arising from oriented planar arc diagrams. This is used to construct an invariant of oriented tangle diagrams with values in the homotopy category attached to the cobordism category. Motivated by Bar-Natan's categorification of the Jones polynomial, it categorifies the quantum $sl_n$ quantum invariants and is adapted to the categorification of the $sl_n$ quantum invariants by Khovanov and Rozansky using matrix factorizations. We conjecture to exist th…

对合Khovanov同调与等变纽结II

Involutive Khovanov homology and equivariant knots II

本文将对合Khovanov同调框架推广到对合缠结，实现了相关同调与不变量的分治加速计算，并得到存在奇异切片圆盘对的强可逆纽结新例子。

Khovanov 同调与等变曲面

Khovanov homology and equivariant surfaces

本文通过精细化 Bar-Natan 同调构造新数值不变量，证明强可逆纽结的等变切片亏格与同痕等变切片亏格之差可任意大。

Categorification of the colored Jones polynomial and Rasmussen invariant of links

We define a family of formal Khovanov brackets of a colored link depending on two parameters. The isomorphism classes of these brackets are invariants of framed colored links. The Bar-Natan functors applied to these brackets produce Khovanov and Lee homology theories categorifying the colored Jones polynomial. Further, we study conditions under which framed colored link cobordisms induce chain transformations between our formal brackets. We conjecture that, for special choice of parameters, Khovanov and Lee homology theories of colored links are functorial (up to sign). Finally, we extend the …

一个用于涡旋链接Khovanov同调的简化复形

A whittled complex for the Khovanov homology of torus links

本文提出了一种算法，用于减少涡旋辫形Khovanov链复形的生成元数量，并给出了简化复形中同调度数的生成元数量的界限。

Khovanov同调的$y$-化

A $y$-ification of Khovanov homology

本文通过构造Khovanov同调的$y$-化及其等变版本，定义了$\mathfrak{sl}_2$作用，并证明其与HOMFLY-PT同调到Khovanov同调的谱序列相容，从而区分具有相同同调的结对。

等变无结数与反演Khovanov同调

Equivariant Unknotting Number and Involutive Khovanov Homology

研究等变无结数与反演Khovanov同调的关系，发现无结数下界由反演Bar-Natan同调的H- torsion阶决定，并识别五种交叉数不超过9的强无结素结满足严格不等式。

An sl(2) tangle homology and seamed cobordisms

We construct a bigraded (co)homology theory which depends on a parameter a, and whose graded Euler characteristic is the quantum sl(2) link invariant. We follow Bar-Natan's approach to tangles on one side, and Khovanov's sl(3) theory for foams on the other side. Our theory is properly functorial under tangle cobordisms, and a version of the Khovanov sl(2) invariant (or Lee's modification of it) corresponds to a=0 (or a=1). In particular, our construction naturally resolves the sign ambiguity in the functoriality of Khovanov's sl(2) homology theory.

关于Khovanov同调的计算复杂性

On computational complexity of Khovanov homology

本文研究了Khovanov同调的计算复杂性，证明了3-辫子的多项式时间算法，并展示了扫描算法在特定条件下的指数时间复杂性。

A Khovanov type invariant derived from an unoriented HQFT for links in thickened surfaces

Two link diagrams on compact surfaces are strongly equivalent if they are related by Reidemeister moves and orientation preserving homeomorphisms of the surfaces. They are stably equivalent if they are related by the two previous operations and adding or removing handles. Turaev and Turner constructed a link homology for each stable equivalence class by applying an unoriented topological quantum field theory (TQFT) to a geometric chain complex similar to Bar-Natan's one. In this paper, by using an unoriented homotopy quantum field theory (HQFT), we construct a link homology for each strong equ…

On Khovanov's cobordism theory for su(3) knot homology

We reconsider the su(3) link homology theory defined by Khovanov in math.QA/0304375 and generalized by Mackaay and Vaz in math.GT/0603307. With some slight modifications, we describe the theory as a map from the planar algebra of tangles to a planar algebra of (complexes of) `cobordisms with seams' (actually, a `canopolis'), making it local in the sense of Bar-Natan's local su(2) theory of math.GT/0410495. We show that this `seamed cobordism canopolis' decategorifies to give precisely what you'd both hope for and expect: Kuperberg's su(3) spider defined in q-alg/9712003. We conjecture an answe…

一些 $ \mathbb{RP}^3 $ 中的链同调

Some link homologies in $ \mathbb{RP}^3 $

本文提出了一种新的链接同调理论，用于研究 $ \mathbb{RP}^3 $ 中的链同调，并引入了不同的 Rasmussen 不变量。

Khovanov Homology, Lee Homology and a Rasmussen Invariant for Virtual Knots

The paper contains an essentially self-contained treatment of Khovanov homology, Khovanov-Lee homology as well as the Rasmussen invariant for virtual knots and virtual knot cobordisms which directly applies to classical knot and classical knot cobordisms. To do so, we give an alternate formulation for the Manturov definition of Khovanov homology for virtual knots and links with arbitrary coefficients. This approach uses cut loci on the knot diagram to induce a conjugation operator in the Frobenius algebra. We then discuss the implications of the maps induced in the aforementioned theory to the…

Khovanov 同调与有理 unknotting

Khovanov homology and rational unknotting

本文提出一个基于 Khovanov 同调的新不变量 $λ$，用于下界估计有理 unknotting 数，并构造了具有任意非负整数值的结示例。

The universal Khovanov link homology theory

We determine the algebraic structure underlying the geometric complex associated to a link in Bar-Natan's geometric formalism of Khovanov's link homology theory (n=2). We find an isomorphism of complexes which reduces the complex to one in a simpler category. This reduction enables us to specify exactly the amount of information held within the geometric complex and thus state precisely its universality properties for link homology theories. We also determine its strength as a link invariant relative to the different topological quantum field theories (TQFTs) used to create link homology. We i…

A 2-category of chronological cobordisms and odd Khovanov homology

We create a framework for odd Khovanov homology in the spirit of Bar-Natan's construction for the ordinary Khovanov homology. Namely, we express the cube of resolutions of a link diagram as a diagram in a certain 2-category of chronological cobordisms and show that it is 2-commutative: the composition of 2-morphisms along any 3-dimensional subcube is trivial. This allows us to create a chain complex, whose homotopy type modulo certain relations is a link invariant. Both the original and the odd Khovanov homology can be recovered from this construction by applying certain strict 2-functors. We …

The Moduli Problem of Lobb and Zentner and the Coloured sl(N) Graph Invariant

Motivated by a possible connection between the $\mathrm{SU}(N)$ instanton knot Floer homology of Kronheimer and Mrowka and $\mathfrak{sl}(N)$ Khovanov-Rozansky homology, Lobb and Zentner recently introduced a moduli problem associated to colourings of trivalent graphs of the kind considered by Murakami, Ohtsuki and Yamada in their state-sum interpretation of the quantum $\mathfrak{sl}(N)$ knot polynomial. For graphs with two colours, they showed this moduli space can be thought of as a representation variety, and that its Euler characteristic is equal to the $\mathfrak{sl}(N)$ polynomial of th…

通过长正合列窥视T(2,n)的Khovanov同调

A Glimpse of the Khovanov Homology of T(2,n) Via Long Exact Sequence

本文通过长正合列从Kauffman括号多项式构建Khovanov同调，展示其在计算T(2,n)扭结同调中的应用，并推广结理论在拉丁美洲的研究。

Khovanov同调：pro-缠绕、导出余极限与谱序列

Khovanov homology: pro-tangles, derived colimits and spectral sequences

本文引入pro-缠绕作为经典缠绕的推广，通过单纯Yoneda嵌入构造Khovanov单纯预层，证明其可表示性，并利用布尔立方分解建立收敛到总Khovanov同调的代数谱序列，给出Reidemeister不变性的函子解释。