Boundary Slopes of 2-Bridge Links

In their paper The space of incompressible surfaces in a 2-bridge link complement, Trans. Amer. Math. Soc. 305(2):575-599, 1988, Floyd and Hatcher explicitly describe all incompressible surfaces in the complement of a 2-bridge link. However, they do not compute the boundary slopes of these surfaces, saying only that it should be possible in principle. In his (unpublished) dissertation, Lash developed an algorithm based on Floyd and Hatcher's work for computing the boundary slopes of 2-bridge links.

This webpage contains two things:


Computing boundary slopes of 2-bridge links is available from the arXiv math.GT/0505442.


The program can compute the boundary slopes of a two-bridge link. The program is written in the programming language Python. You will need a Python interpreter (version 1.5 or newer) to run the program. These are free and available for virtually every platform from the Python home page. If you're using UNIX, you can see if your system has python installed by typing which python (Linux systems almost always have Python installed). To install, download the proper file: To run the file in: The program will then give you all the instructions you will need.

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