LINKS, KNOTS, AND KNOTTED LABYRINTHS IN BISTABLE SYSTEMS

The existence of stable links and knots is demonstrated in three-dimen sional, bistable, chemical media. The reaction-diffusion medium segreg ates into regions of high and low concentration separated by sharp int erfaces. The interfaces repel at short distances so that domains with various topologies are possible, depending on the initial conditions a nd system parameters. Front instabilities can give rise to knotted lab yrinthine patterns. A lattice-gas model whose mean-field limit is the FitzHugh-Nagumo equation is described and implemented to carry out the simulations.