
...are regular. this implies that unary pushdown
automata and unary contextfree grammars can be...the
descriptions of the given pushdown automata and contextfree grammars. as a main consequence, we are able to prove a log log
n lower bound for the workspace used by...

...is regular. this implies that unary contextfree grammars and unary pushdown automata can be transformed into equivalent finite automata. in this paper, we study...grammars. we also give upper bounds for the number of states of finite automata simulating unary pushdown automata. as a main consequence, we...

...are regular. this implies that unary contextfree grammars and unary pushdown automata are equivalent to finite automata. in this talk, we present...grammars. we also give upper bounds for the number of states of finite automata simulating unary pushdown automata. there are some consequences in space complexity: we are able to...
Published in 2002.

...well as “probabilistic plus nondeterministic” pushdown automata and auxiliary pushdown automata are studied. these models are analogous to their counterparts with nondeterministic and alternating states. complete characterizations in...languages recognized by polynomial timebounded, logarithmic spacebounded auxiliary pushdown automata with probabilistic states and with “probabilistic plus nondeterministic” states. also, complexity lower bounds are given for the classes...

...well as probabilistic plus nondeterministic pushdown automata and auxiliary pushdown automata are studied. these models are analogous to their counterparts with nondeterministic and alternating states. complete characterizations in...languages recognized by polynomial timebounded, logarithmic spacebounded auxiliary pushdown automata with probabilistic states and with probabilistic plus nondeterministic states. also, complexity lower bounds are given for the classes...

...logdcfl.
we investigate the membership and counting problems for generalisations of visibly pushdown automata, defined using the notion
of...this uses the fact that pushdown transducers are sufficient to compute the stack heights of all realtime heightdeterministic
pushdown automata, and yields a candidate arithmetization of...

...each accepted word. while unambiguous pushdown
automata induce a language family strictly in between the deterministic and general contextfree languages, unambiguous finite
automata capture the regular languages, that...the present paper, we summarize and discuss developments
relevant to (un)ambiguous finite automata and pushdown automata problems from the descriptional complexity...
Published in 2010.

...of twoway nondeterministic storage automata with auxiliary
worktape that is logarithmicspace bounded. moreover, we also consider acyclic graphs in the underlying reachability instance,
obtaining a lower bound result for auxiliary storage automata that are simultaneously space and time restricted.
...

...for identification of deterministic finite automata (dfa) which is based on...we reduce the
sat search space by adding lower bound information using a fast max...

...investigate the complexity of satisfiability and pushdown modelchecking of the extension...plus two). moreover, we provide lower bounds which match the upper bounds for the case of finite...