Canonical scattered context generators of sentences with their parses

Scattered context generators derive their sentences followed by the corresponding parses. This paper discusses their two canonical versions, which make this derivation either in a leftmost or rightmost way. It demonstrates that for every recursively enumerable language, L, there exists a canonical scattered context generator whose language consists of L’s sentences followed by their parses. In fact, this result is established based on the generators containing no more than six nonterminals.