This is suggested by Anthony Burgess as the shortest ever work of science fiction, in "Les Cahiers de la nouvelle", "Journal of the Short Story in English", January 1984, pp. 31-47. Universite d'Angers.

Contrast with Hemingway's 6-word short story: For Sale. Baby Shoes. Never worn.

From my own memory, confirmed by the rec.arts.sf.written FAQ, and