Abstract. While visibly pushdown languages properly generalise regular languages and are properly contained in deterministic context-free languages, the complexity of their members...
Abstract. We define the notion of height-deterministic pushdown automata, a model where for any given input string the stack heights during any (nondeterministic) computation on t...
We show that fixed membership testing for many interesting subclasses of multi-pushdown machines is no harder than for pushdowns with single stack. The models we consider are MVPA...
Maximal word functions occur in data retrieval applications and have connections with ranking problems, which in turn were rst investigated in relation to data compression 21 . By ...