Abelian cascade dynamics in bootstrap percolation

The culling process in bootstrap percolation is Abelian since the final sta ble configuration does not depend on the details of the updating procedure. An efficient algorithm is devised using this idea for the determination of the bootstrap percolation threshold in two dimension which takes L-2 time compared to the L-3 logL in the conventional method. A generalised bootstra p percolation allowing many particles at a site is studied where continuous phase transitions are observed for all values of the threshold parameter. Similar results are also obtained for the continuum bootstrap percolation m odel. (C) 1998 Published by Elsevier Science B.V. All rights reserved.