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                Department of Mathematical Sciences                       
                   The Johns Hopkins University                           
                                                                        
                              SEMINAR                                
                                                                        
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Professor John C. Wierman                         April 20, 2000
Department of Mathematical Sciences               304 Whitehead Hall
The Johns Hopkins University                      Preseminar: 3:00 p.m.
                                                  Refreshments: 3:30 p.m.
                                                  Seminar: 4:00 p.m.

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      BOUNDS FOR CRITICAL PROBABILITIES IN PERCOLATION MODELS

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                             ABSTRACT

The talk will present a survey of rigorous bounds for percolation
critical probabilities for various two-dimensional lattices.  An improved
computational approach for the substitution method for proving bounds will
be described.  Recent results and work in progress will be given for the
hexagonal lattice site-percolation model and the Kagome lattice
bond-percolation model.

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