Filters








88 Hits in 2.7 sec

On omega context free languages which are Borel sets of infinite rank

Olivier Finkel
2003 Theoretical Computer Science  
We proved in (Topological properties of omega context free languages, Theoretical Computer Science, 262 (1-2) (2001) 669-697) that the class of !  ...  -CFL exhausts the ÿnite ranks of the Borel hierarchy, and in (Borel hierarchy and omega context free languages, Theoretical Computer Science, to appear) that there exist some !  ...  Acknowledgements Thanks to the anonymous referees for useful comments on a previous version of this paper.  ... 
doi:10.1016/s0304-3975(02)00327-4 fatcat:uufsvfxyyzeufivmyrekrt3f3m

Topological properties of omega context-free languages

Olivier Finkel
2001 Theoretical Computer Science  
This paper is a study of topological properties of omega context-free languages (!-CFL). We ÿrst extend some decidability results for the deterministic ones (!  ...  Thesis, Università e Paris 7, March 1992) about omega powers of ÿnitary languages. We show that B uchi-Landweber's Theorem cannot be extended to even closed !  ...  Thanks also to the anonymous referees for useful comments on a previous version of this paper.  ... 
doi:10.1016/s0304-3975(00)00405-9 fatcat:3dxegiguxvcadifqzisxns5pay

On Omega Context Free Languages which are Borel Sets of Infinite Rank [article]

Olivier Finkel
2010 arXiv   pre-print
of Infinite Computations, In:"A Decade of Concurrency", Springer LNCS 803 (1994), 583-621].  ...  This paper is a continuation of the study of topological properties of omega context free languages (omega-CFL).  ...  Thanks to the anonymous referees for useful comments on a previous version of this paper.  ... 
arXiv:1005.5633v1 fatcat:2vfujzo3bjb2bkfb7ajtngssry

Borel Hierarchy and Omega Context Free Languages [article]

Olivier Finkel
2011 arXiv   pre-print
And one cannot decide whether an omega-CFL is a Borel set.  ...  Then we prove some recursive analogues to preceding properties: in particular one cannot decide whether an omega-CFL is an arithmetical set.  ...  Then at any moment of any computation the word in the pushdown store is in the form E n Z 0 where n is an integer ≥ 0.  ... 
arXiv:1101.3443v1 fatcat:mchn5kjacvautj2yks4psn5aqa

Borel hierarchy and omega context free languages

Olivier Finkel
2003 Theoretical Computer Science  
-languages accepted by omega pushdown automata, considering various acceptance conditions for omega words.  ...  -regular language accepted by a B uchi automaton M , the resulting machine M is just a one counter machine, i.e. a pushdown machine having a stack alphabet = {Z 0 ; E}, where Z 0 is the bottom symbol which  ... 
doi:10.1016/s0304-3975(02)00042-7 fatcat:ea2ptno4wfhxrm25rvdcnf7z7y

Wadge hierarchy of omega context-free languages

Olivier Finkel
2001 Theoretical Computer Science  
The main result of this paper is that the length of the Wadge hierarchy of omega context-free languages is greater than the Cantor ordinal 0, and the same result holds for the conciliating Wadge hierarchy  ...  In the course of our proof, we get results on the Wadge hierarchy of iterated counter !-languages, which we deÿne as an extension of classical (ÿnitary) iterated counter languages to !-languages.  ...  As in the general case of pushdown machines, we can consider together ÿnite and inÿnite runs of a k-iterated counter pushdown machine given with two state sets K 1 and K 2 (one is used for the acceptation  ... 
doi:10.1016/s0304-3975(01)00008-1 fatcat:gijdxowzszfcbekqgf7hxykxda

Omega Automata and its Classes

Natasha Singh, Ajay Kumar
2018 Current Science  
In addition, this paper also summarizes the applicability of omega automata in various interdisciplinary fields.  ...  Language generated by omega-automata is used for representing non-terminating computations.  ...  (iv) Equivalence problem for ωdeterministic pushdown automata is still an open problem. (v) The concept of visibly pushdown automata and infinity games can be explored in the near future.  ... 
doi:10.18520/cs/v115/i11/2042-2051 fatcat:byu5hbxpnbaclbp2rkx3qa6uhm

Good-for-games $\omega$-Pushdown Automata

Karoliina Lehtinen, Martin Zimmermann
2022 Logical Methods in Computer Science  
We introduce good-for-games $\omega$-pushdown automata ($\omega$-GFG-PDA). These are automata whose nondeterminism can be resolved based on the input processed so far.  ...  Our main results are that $\omega$-GFG-PDA are more expressive than deterministic $\omega$- pushdown automata and that solving infinite games with winning conditions specified by $\omega$-GFG-PDA is EXPTIME-complete  ...  This is beyond the capabilities of finite-state machines and blocks the stack of a pushdown machine implementing r from performing other computations.  ... 
doi:10.46298/lmcs-18(1:3)2022 fatcat:2nm6ks4rz5efznj3bgpw6md2ay

Decision Problems for Deterministic Pushdown Automata on Infinite Words

Christof Löding
2014 Electronic Proceedings in Theoretical Computer Science  
The article surveys some decidability results for DPDAs on infinite words (omega-DPDA).  ...  Furthermore, we present some new results on the parity index problem for omega-DPDAs.  ...  We are mainly concerned with deterministic pushdown automata in this work. We first define pushdown machines, which are pushdown automata without acceptance condition.  ... 
doi:10.4204/eptcs.151.4 fatcat:gxxf7gxwmnhnfmgvsjiskdoj3y

Ambiguity in omega context free languages

Olivier Finkel
2003 Theoretical Computer Science  
-CFL) accepted by B uchi or Muller pushdown automata. We show that these notions may be deÿned independently of the B uchi or Muller acceptance condition which is considered.  ...  We extend the well-known notions of ambiguity and of degrees of ambiguity of ÿnitary context free languages to the case of omega context free languages (!  ...  Acknowledgements Thanks to Jean-Pierre Ressayre and Jacques Duparc for many useful discussions about Wadge and Wagner hierarchies, and to Pierre Simonnet for communicating his result on analytic omega  ... 
doi:10.1016/s0304-3975(02)00584-4 fatcat:zohu57u5t5dzrh6yjhpiqdf2pe

Page 2219 of Mathematical Reviews Vol. , Issue 91D [page]

1991 Mathematical Reviews  
(F-PARIS7-LI) Pushdown automata on infinite trees and omega-Kleene closure of context-free tree sets.  ...  / log n) time bound for the simulation of a deterministic f(n) time-bounded multi- tape Turing machine on a deterministic one-tape off-line Turing machine and to an O(n*/,/logn) time bound for transposing  ... 

Topological Complexity of Context-Free omega-Languages: A Survey [article]

Olivier Finkel
2013 arXiv   pre-print
In particular, we consider the Borel hierarchy and the Wadge hierarchy of non-deterministic or deterministic context-free omega-languages.  ...  We survey recent results on the topological complexity of context-free omega-languages which form the second level of the Chomsky hierarchy of languages of infinite words.  ...  Unlike the case of finite automata, deterministic M P DA do not define the same class of ω-languages as non deterministic M P DA. Let us now define deterministic pushdown machines. Definition 9.  ... 
arXiv:0806.1413v2 fatcat:jx2eoqnupbdg3eyynkz3u2ygbi

Highly Undecidable Problems For Infinite Computations [article]

Olivier Finkel
2009 arXiv   pre-print
These very surprising results provide the first examples of highly undecidable problems about the behaviour of very simple finite machines like 1-counter automata or 2-tape automata.  ...  Topological and arithmetical properties of 1-counter omega-languages, context free omega-languages, or infinitary rational relations, are also highly undecidable.  ...  On the other hand, an ω-language L ⊆ X ω is in the class Σ 1 1 iff it is accepted by a non deterministic Turing machine with a 1 ′ or Büchi acceptance condition, [Sta97] .  ... 
arXiv:0901.0373v1 fatcat:hto3r4zibjbz7byafrgurbdw5q

Topology and Ambiguity in Omega Context Free Languages [article]

Olivier Finkel
2008 arXiv   pre-print
In particular, using known facts from classical descriptive set theory, we prove that non Borel omega context free languages which are recognized by B\"uchi pushdown automata have a maximum degree of ambiguity  ...  On the other side we show that methods used in the study of omega context free languages can also be applied to study the notion of ambiguity in infinitary rational relations accepted by B\"uchi 2-tape  ...  We thank Dominique Lecomte and Jean-Pierre Ressayre for useful discussions and the anonymous referees for useful comments on a preliminary version of this paper.  ... 
arXiv:0801.0533v1 fatcat:upiqvt2lavebtfbhsu24vrxney

Property grammars and table machines

R. E. Stearns, P. M. Lewis
1968 9th Annual Symposium on Switching and Automata Theory (swat 1968)  
., A Regularity Test for Pushdown Machines, Information & Control, vol. 11, #1, Sept. 1967, 323-340. 17.  ...  time on Turing machines and developed a theory of complexity classes.  ... 
doi:10.1109/swat.1968.23 dblp:conf/focs/StearnsL68 fatcat:a6z3qaeg7ffw5nlqxxtjzefl44
« Previous Showing results 1 — 15 out of 88 results