There is a set of restrictions on comparative constructions which is characterized exactly in terms of the Be hierarchy. Consider, by way of illustration, the following sentences:

(12) (a) (i) a cannon is more deadly than a pistol

              (ii) a pistol is more deadly than a cannon

              (iii) *a cannon is more deadly than a gun

              (iv) *a pistol is more deadly than a gun

        (b) (i) *a gun is more deadly than a cannon

              (ii) *a gun is more deadly than a pistol

An examination of the compared nouns in the sentences above in terms of the Be hierarchy which involves weapons, (13), reveals that the restrictions observed in these sentences can be expressed in terms of the dominance relation obtaining in this hierarchy:

The comparative constructions in (12) are grammatical just in case a comparing noun neither dominates nor is dominated by a compared noun in the Be hierarchy. Thus, ‘pistols’ and ‘cannons’ may be compared. Furthermore, any item which ‘pistol’ dominates (e.g. ‘derringer’) can be compared either with ‘cannon’ or any other item dominated by ‘ gun ’ which neither dominates nor is dominated by ‘ pistol ’ (e.g. ‘rifle’) as in the following examples:

(14) (a) a cannon is more deadly than a derringer

        (b) a rifle is more deadly than both a derringer and a cannon

Although the derivation of comparative constructions in general has not been fully resolved, it is nonetheless clear that certain restrictions on these constructions require reference to a lexical Be hierarchy.