On acceptance conditions for membrane systems: characterisations of L and NL

Abstract

In this paper we investigate the affect of various acceptance conditionson recogniser membranesystems without dissolution. We demonstrate that two particular acceptanceconditions (one easier toprogram, the other easier to prove correctness) both characterisethe same complexity class, NL. Wealso find that by restricting the acceptance conditions we obtaina characterisation of L. We obtainthese results by investigating the connectivity properties of dependencygraphs that model membranesystem computations.