  The O(3) sigma model in two spatial dimensions admits topological
(Bogomol'nyi) lower bound on its energy. This paper proposes a lattice version
of this system which maintains the Bogomol'nyi bound and allows the explicit
construction of static solitons on the lattice. Numerical simulations show that
these lattice solitons are unstable undersmall perturbations; in fact, their
size changes linearly with time.
