St. Lawrence University     Festival of Science 2002
 
Sarah Woodworth

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Ramsey Number Examination

Faculty Advisor: Brian Ladd

Poster Presentation

This project looks into how Ramsey Numbers are solved using computers.  A Ramsey Number is the smallest graph size that must contain either a clique of a given size or an anti-clique of a given size.  A Ramsey Number is written as R(m, n) where m is the clique size and n is the anti-clique size that we are looking for.  Finding Ramsey Numbers has proven to be extremely difficult due to the exponential growth of the problems.  Recently, computers have been used to help find new numbers, but even their bounds are quickly reached.  For my project, I looked into and experimented with how computers can be used to find Ramsey Numbers.  This is done using a brute force technique to create all the graphs of a given size and determine if they contain a clique of size m or an anti-clique of size n.  The first part of the semester I have spent creating a program that can determine if a graph of a given size is the Ramsey Number for a given m and n.  Now that this program works, I have been working to increase the speed of the program to try to obtain larger results.  Some speed was gained by creating an iterative version for the two main recursive functions that I used.  Speed has also been increased by creating code to start and stop the program from various positions allowing the program to be run using different machines simultaneously.  I should now be able to find R(3, 4) after running my program for a few days, but R(4, 4) is probably not possible to find by the end of the semester.
 


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