Published online by Cambridge University Press: 20 November 2018
In a lecture in 1966 (see [6]), the second author considered briefly those first order properties which hold for a lattice if and only if they hold for the lattice of all ideals of . The best known examples of such properties are those given by identities. The well-known connection between the modular identity ϵ and the five-element nonmodular lattice transforms the above result for ϵ into the following statement: is a sublattice of a lattice if and only if is a sublattice of .