Gordon and the cat

[greek]

Consider the sentences in (6). Assuming that the reference of the name "Gordon" and the discourse context are held constant for all the sentences in (6), then the sentences in (6.b) to (6.i) are semantically related to the sentence in (6.a), even though it is not always the case that there is a direct syntactic relation between them.

(6) a. Gordon stroked a cat.
      b. A cat was stroked.
      c. There was a cat.
      d. No-one stroked a cat.
      e. There are no such things as cats.
      f. A cat was stroked by Gordon.
      g. It was Gordon who stroked the cat.
      h. Gordon touched a cat.
      i. Gordon stroked an animal.

The relation between the sentences in (6.a) and those in (6.b) and (6.c) is one of entailment, as it is intuitively impossible for it to be true that Gordon stroked a cat on some occasion without it also being true that a cat was stroked or that there existed a cat to be stroked on that occasion.