Contents

1. Introduction
2. Getting the program running
3. Using the program
4. Source Code
5. Contact

Introduction

Java Knot Sketcher allows you to calculate the Gauss code and DT notation by drawing a knot diagram. The functionality is similar to that of LinkSmith component of Knotscape by Morwen Thistlethwaite.

Getting the program running

This implementation is written in Java and requires Java Web Start, which is installed as part of J2SE v 1.4.2_04 JRE. Download and execute the appropriate installer program for your particular platform.

If Java 1.4.2 is installed, click on the link found on this page. Wait a while for it to download (~15 KB), then the program should appear and run on your machine.

Using the program

The general idea is to draw a (polygonal) knot diagram that is equivalent to the knot diagram you are interested in.

1. Drawing the knot
   First you start at some point on the knot and trace out a similar knot on the screen, disregregarding the handedness of the crossings. Clicking on the canvas will fix a corner on the knot. If you make an error, you can back up by right-clicking. You will not be able to:
   • make hard corners,
   • place an line segment too close to a vertex of another line segment or
   • place a line segment too close to a crossing.
   Eventually you will close the loop by clicking on the initial vertex.
2. Changing the orientation or the handedness of the crossings
   When the knot is closed off, the program will compute the various notations it knows about. To change the handedness of a crossing, just click on it. The notation will be updated automatically. Through the menu, you may also
   • reverse the handedness of all the crossings (mirror image),
   • reverse the orientation of the knot diagram, or
   • make the diagram alternating.

Source Code

You can download the source code for Knot Sketcher. It is licensed under the General Public License.

Contact

If you have any suggestions, comments, or questions, please email Jiho Kim.