Journal of Knot Theory and Its Ramifications

We introduce and investigate dichromatic singular links. We also construct disingquandles and use them to define counting invariants for unoriented dichromatic singular links. We provide some examples to show that these invariants distinguish some dichromatic singular links.

In this paper, we introduce a new polynomial invariant of planar (but not spherical) knotoids, which we call the winding signed sum polynomial. This Laurent polynomial invariant of planar knotoids denoted by ${\beta }_K$ is a type-one Vassiliev invariant. This invariant might tell whether a planar knotoid is a zero-height or nonzero-height planar knotoid. It also might distinguish between a planar knotoid and its inverse, while the affine index polynomial defined by Gügümcü and Kauffman in [New invariants of knotoids, Eur. J. Combin. 65 (2017) 186–229] (that is also a type-one Vassiliev invariant) cannot distinguish between a planar knotoid and its inverse. We also define some geometric invariants of planar knotoids, and give lower bounds for these invariants using the winding signed sum polynomial, which helps in computing these geometric invariants that are easy to define, but hard to calculate.

A positive braid is called tiny when it is a product of generators and each generator being used at most once. We will present a commuting criterion for tiny braids and explore the structure of the centralizer of a tiny braid in the set of positive braid monoids. We will also discuss various combinatorial properties of the centralizer and a few invariants of an associated commuting graph. Finally, we will provide affirmative answers to a couple of open questions related to the commuting graph of tiny braids.

In a group, a nontrivial element is called a generalized torsion element if some non-empty finite product of its conjugates is equal to the identity. There are various examples of torsion-free groups which contain generalized torsion elements. We can define the order of a generalized torsion element as the minimum number of its conjugates required to generate the identity. In previous works, three-manifold groups which contain a generalized torsion element of order two are determined. However, there are few previous studies that examine the order of a generalized torsion element bigger than two. In this paper, we focus on Seifert fibered spaces with boundary, including the torus knot exteriors, and construct concretely generalized torsion elements of order $3$, $4$, $6$ and others in their fundamental groups.

Quandles with good involutions, which are called symmetric quandles, can be used to define invariants of unoriented knots and links. In this paper, we determine the necessary and sufficient condition for good involutions of a generalized Alexander quandle to exist. Moreover, we classify all good involutions of a connected generalized Alexander quandle up to symmetric quandle isomorphisms.

A state model for Kauffman polynomial of Dubrovnik-version is described using Gauss diagrams. Based on the state model, the Gauss diagram formulae for Vassiliev invariants are given from the coefficients of Kauffman polynomial following the method of Chmutov and Polyak. Some arrow diagram identities are given to simplify the Gauss diagram formulae of order 3, which give Polyak–Viro and Chmutov–Polyak formulae for the Vassiliev invariant of order 3. The models of Kauffman polynomial and HOMFLY-PT polynomial give different Gauss diagram expressions when specializing in Jones polynomial.

We give examples of a linear combination of algebraic knots and their mirrors that are algebraically slice, but whose topological and smooth four-genus is two. Our examples generalize an example of non-slice algebraically slice linear combination of iterated torus knots obtained by Hedden, Kirk and Livingston. Our main tool is a genus bound from Casson–Gordon theory and a cabling formula that allows us to compute effectively these invariants.