Published online by Cambridge University Press: 12 March 2014
By means of an Ehrenfeucht-Mostowski construction we obtain an automorphism theorem for a syntactically characterized class of Laa-theories comprising in particular the finitely determinate ones. Examples of Laa-theories with only rigid models show this result to be optimal with respect to a classification in terms of prenex quantifier type: Rigidity is seen to hinge on quantification of type … ∀ … stat … permitting of the parametrization of families of disjoint stationary systems by the elements of the universe.