Journal of Knot Theory and Its Ramifications

We give a new proof of the conformal invariance of the writhe of a knot from a conformal geometric vewpoint.

We define an invariant for two component spatial graphs. Although the definition of the invariant is alike a linking number, it is different from the absolute value of a linking number. We show that the invariant is not a finite type invariant.

We determine whether singular charts without black vertices can be deformed to the trivial chart by reducing node-pairs only. It is not true if the degree of the singular chart is at least four, while it is true if the degree is at most three.

This paper summarizes substantive new results derived by a student team (the first three authors) under the direction of the fourth author at the 2008 session of the KSU REU "Brainstorming and Barnstorming". The main results show that the construction of the inner automorphism group of a quandle gives rise to a functor from the category of quandles and surjective quandle homomorphisms to the category of groups, characterize quotient maps of quandles which do not change the group of inner automorphims, and characterize those normal subgroups of the inner automorphism group which arise as kernels of homomorphisms induced by quandle surjections.

We give an upper bound for the dealternating number of a closed 3-braid. As applications, we determine the dealternating numbers, the alternation numbers and the Turaev genera of some closed positive 3-braids. We also show that there exist infinitely many positive knots with any dealternating number (or any alternation number) and any braid index.

We calculate the rational Khovanov homology of a class of pretzel knots by using the spectral sequence constructed by Turner. Moreover, we determine Rasmussen's s-invariant of almost all pretzel knots P(p, q, r) by using Turner's spectral sequence, a sharper slice-Bennequin inequality, and a skein inequality.

We construct an infinite sequence of invariants for surface curves by using the word theory introduced by Turaev. We modify these invariants to various classes of curves: plane closed curves, long curves and fronts. For a plane closed curve, for example, these modified invariants contain Arnold's basic invariants. We also discuss how curves are classified by these modified invariants.