On Quantum Context-Free Grammars

Quantum computing is a relatively new field of computing, which utilises the fundamental concepts of quantum mechanics to process data. The seminal paper of Moore et al. [2000] introduced quantum grammars wherein a set of amplitudes was attached to each production. However they did not study the final probability of the derived word. Aruja et al. [2025] considered conditions for the well-formedness of quantum context-free grammars (QCFGs), in order to ensure that the probabilty of the derived word does not exceed one. In this paper we propose certain necessary and sufficient conditions (also known as unitary conditions) for well-formedness of QCFGs