Corrections

In this column recently we erroneously quoted Michigan state Senator Carl Levin as saying, “a mapping for a manifold M is structurally stable if any perturbation is topologically conjugate to , where is a function such that is close to and that the first r derivatives of are also close to the respective derivatives of ”. State Senators are notoriously shy, reclusive, almost mythological creatures and it was not our intention to embarrass one by printing his name where anyone might see it. We apologize for the error.