Abstract
We consider in this paper so called simple bracketed languages having special limitations. They are sometimes used for the definitions of some grammatical structures of programming languages. Generally speaking, these languages are context-free, but not deterministic context-free, i.e., they cannot be defined by deterministic push-down automata. For the simple bracketed languages having special limitations, the equivalence problem is decidable.
We obtain the sufficient conditions for the representation some language by special sequences of simple bracketed languages. We also consider the examples of grammatical structures as the simple bracketed languages. Therefore, we can decide equivalence problem for some grammatical structures of programming languages, and such structures define neither regular, nor deterministic context-free languages.