Invariants of weak equivalence in primitive matrices

Weak equivalence of primitive matrices is a known invariant arising natural ly from the study of inverse limit spaces. Several new invariants for weak equivalence are described. It is proved that a positive dimension group iso morphism is a complete invariant for weak equivalence. For the transition m atrices corresponding to periodic kneading sequences, the discriminant is p roved to be an invariant when the characteristic polynomial is irreducible. The results have direct application to the topological classification of o ne-dimensional inverse limit spaces.