A crucial problem for lexicon design and construction is how to represent diathesis alternation phenomena, which occur when the same verb can appear in a variety of subcategorisation frames related to one another through valency alternations. Typical examples are:
|(134)||John ate the cake|
|(136)||John broke the glass|
|(137)||The glass broke|
Examples (134) and (135) exemplify the indefinite object alternation, according to which a given slot filler -- the object in the case at hand -- is optionally expressed. Examples (136) and (137) illustrate the causative-inchoative alternation, where the same slot filler can be associated with different syntactic functions, either the direct object of the transitive reading or the subject of the intransitive reading of the same verb.