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Genetic Algorithms applied to Problems of Forbidden Configurations
A simple matrix is a (0,1)-matrix with no repeated columns. For a (0,1)-matrix F, we say a (0,1)-matrix A avoids F (as a configuration) if there is no submatrix of A which is a row and column permutation of F. Let βA β denote the number of columns of A. We define forb(m,F) = max{βA β : A is an m-rowed simple matrix that avoids F}. Define an extremal matrix as an m-rowed simple matrix A with that avoids F and βA β = forb(m,F). We describe the use of Local Search Algorithms (in particular a Genetic Algorithm) for finding extremal matrices. We apply this technique to two forbidden configurations in turn, obtaining a guess for the structure of an m Γ forb(m,F) simple matrix avoiding F and then proving the guess is indeed correct. The Genetic Algorithm was also helpful in finding the proof