  We study Pfaffian random point fields by using the Moore-Dyson quaternion
determinants. First, we give sufficient conditions that ensure that a self-dual
quaternion kernel defines a valid random point field, and then we prove a CLT
for Pfaffian point fields. The proofs are based on a new quaternion extension
of the Cauchy-Binet determinantal identity. In addition, we derive the Fredholm
determinantal formulas for the Pfaffian point fields which use the quaternion
determinant.
