Isomorphic but not lower base-isomorphic cylindric algebras of finite dimension
The author shows that a certain theorem of Serény is best possible; Serény's theorem is an algebraic version of Vaught's theorem on the existence of prime models of atomic theories in countable languages. A corollary of the constructions here is that Vaught's theorem does not extend to languages with finitely many (but at least 2) variables.
algebraic version of Vaught's theorem on the existence of prime models
scientific article; zbMATH DE number 4123728