Konvejeva notacija u teoriji čvorova i njena primena u metodima za određivanje rastojanja čvorova

Abstract

Glavni sadržaj ovog rada je konstrukcija novih metoda za određivanje različitih tipova rastojanja čvorova - rastojanja čvorova nastalih promenama preseka (Gordijeva rastojanja) i rastojanja čvorova nastalih zaravnjivanjem (s-rastojanja). U radu su predstavljeni različiti načini prikazivanja čvorova, a posebno model ogledalskih krivih. Prikazana je primena ovog modela, kodiranje čvorova u njemu, uveden metod za određivanje čvorova predstavljenih ovim modelom i izvedeni svi čvorovi koji mogu biti smešteni u mreže dimenzija p × q (p ≤ 4, q ≤ 4). Detaljnije su opisane i različite notacije čvorova, a poseban akcenat je postavljen na Konvejevu notaciju i njena topološka svojstva. Konvejeva notacija ima glavnu ulogu u dobijanju novih rezultata u ovom radu...

A main focus of the paper is construction of new methods for defining diverse knot distance types - the distance of knots made by crossing changes (Gordian distance) and the distance among knots made by crossing smoothing (smoothing distance). Different ways of knots presentation are introduced, with objective to a mirror curve model. It is presented a purpose of the model, coding of knots, by using the model preferences, as well as introduction of a method to determinate a knots presented by the model and derived all the knots that could be placed to a nets dimensions p×q (p ≤ 4, q ≤ 4). Diverse knot notations are described into details, with a focus to Conway’s notation and its topological characteristics. As it is known, a present algorithms are based on an algebra of chain fractions, that are in close relation with a presentation of rational knots, which results in an absence of a huge number of non-rational knots, in an existing Gordian’s distance tables. The subject of the paper is an implementation of methods with bases on determination of new distances equal 1. The methods are based on a non-minimal presentation of rational and non-rational knots, generation of algorithms established on geometrical characteristics of Conway’s notation and a weighted graph search. The results are organized into Gordian’s distance knots tables up to 9 crossings, and have been enclosed with the paper. In order to append the table with knots having a bigger number of crossings, it has been suggested a method for extension of results for knot families. Using facts of relation among Gordian’s numbers and smoothing numbers, a new method for smoothing number determination is presented, and results in a form of lists for knots not having more then 11 crossings. In conjunction with Conway’s notation concept and the method, algorithms for a smoothing distance are generated. New results are organized in knot tables, up to 9 crossings, combined with previous results, and enclosed with the paper. A changes and smoothing to a knot crossing could be applied for modeling topoisomerase and recombinase actions of DNA chains. It is presented the method for studying changes introduced by the enzymes. A main contribution to the paper is the concept of Conways notation, used for all relevant results and methods, which led to introduction of a method for derivation a new knots in Conways notation by extending C-links. In a lack of an adequat pattern for an existing knot tables in DT-notation, there is usage of a structure based on topological knot concepts. It is proposed a method for knot classification based on Conways notation, tables of all knots with 13 crossings and alternated knots with 14 crossings has been generated and enclosed. The subject of the paper takes into consideration Bernhard-Jablan’s hypothesis for a determination of unknotting number using minimal knot diagrams. The determination is crucial in computation of diverse knot distances. The paper covers one of main problems in knot theory and contains a new method of knot minimization. The method is based on relevance of local and global minimization...