#EXPRESSING QUERIES AS FINITE STATE AUTOMATA VERIFICATION#

You may submit a pre-print of a paper that your presentation is based on, but you are not required to do that.ДЄbstract: Games on graphs is a crucial theoretical concept in Logic and Automata Theory, and has found many applications in verification and synthesis. There are no formal proceedings and we encourage submission of work presented elsewhere. Submissions will not lead to publications. The Abstract should list clearly co-authors, if any. We expect you to present your favourite result of the year, so there should be at most one submission per speaker. They can concern any recently published, to be published, or ongoing work of the speaker. Hence, submissions should have a single author - the speaker.

It should serve as a proposal for a presentation. Submissions should take the form of a short abstract of up to two pages describing the content of the presentation and its interest. Representative areas include, but are not restricted to: We encourage you to attend and present your best work, be it already published or not, at the Highlights conference. Papers from these areas are dispersed across many conferences, which makes them difficult to follow.ДЄ visit to the Highlights conference should offer a wide picture of the latest research in the field and a chance to meet everybody in the community, not just those who happen to publish in one particular proceedings volume. It aims at integrating the community working in these fields. 1.HIGHLIGHTS 2020 is the eighth conference on Highlights of Logic, Games and Automata. The paper shows that, for reasoning about data trees, the forward fragment of the calculus with one register is a powerful alternative to a recently proposed first-order logic with two variables. As consequences, decidability is obtained for two datasensitive fragments of the XPath query language.

Allowing backward modal operators or two registers causes undecidability. The proofs use alternating tree automata which have registers, and establish correspondences with nondeterministic tree automata which have faulty counters. The main results in the paper are that, for the fragment with forward modal operators and one register, satisfiability over finite data trees is decidable but not primitive recursive, and that for the subfragment consisting of safety formulae, satisfiability over countable data trees is decidable but not elementary. A freeze quantifier stores in a register the datum labelling the current tree node, which can then be accessed for equality comparisons deeper in the formula. For expressing data-sensitive properties, the calculus is equipped with freeze quantification. A data tree is an unranked ordered tree whose every node is labelled by a letter from a finite alphabet and an element (вЂњdatumвЂќ) from an infinite set. 1.ДЄn alternation-free modal Вµ-calculus over data trees is introduced and studied. We also prove that surprisingly, over infinite data words, LTL в†“ without the вЂuntilвЂ™ operator, as well as nonemptiness of one-way universal register automata, are undecidable even when there is only 1 register. We show that the future-time fragment of LTL в†“ which corresponds to FO 2 over finite data words can be extended considerably while preserving decidability, but at the expense of non-primitive recursive complexity, and that most of further extensions are undecidable. Previously undiscovered connections among those formalisms, and to counter automata with incrementing errors, enable us to answer several questions left open in recent literature. The only predicate available on data is equality. We investigate relative expressiveness and complexity of standard decision problems for LTL with the freeze quantifier (LTL в†“), 2-variable first-order logic (FO 2) over data words, and register automata. To refer to the data, temporal logics are extended with the freeze quantifier, first-order logics with predicates over the data domain, and automata with registers or pebbles. Examples include timed words and XML documents. A data word is a word over a finite alphabet, together with a datum (an element of an infinite domain) at each position. Temporal logics, first-order logics, and automata over data words have recently attracted considerable attention.

Expressing queries as finite state automata