24 Automatic groups - recent progress 2010-01-07T09:36:47.850

20 congruence on words: having the same (scattered) subwords of length at most n 2013-06-11T13:06:37.120

16 Status of an open problem about semilinear sets 2011-04-01T13:16:40.677

16 What's the difference between ZFC+Grothendieck, ZFC+inaccessible cardinals and Tarski-Grothendieck set theory? 2012-07-22T00:38:00.587

15 Representing mathematical statements as SAT instances 2017-12-27T12:37:59.317

14 Is there an unambiguous CFL whose complement is not context-free? 2014-03-09T01:30:45.553

13 Is there a natural family of languages whose generating functions are holonomic (i.e. D-finite)? 2009-12-08T22:26:27.953

12 Complementation of $\omega$-regular languages in reverse mathematics 2011-03-08T14:18:38.750

12 Reference request: exponential growth rates of subword-closed languages are integers 2016-04-07T21:00:18.317

11 Why do I find Category Theory mostly just a way to make simple things difficult? 2009-10-24T09:46:47.373

11 A language complete for NP intersection co-NP 2010-08-08T04:51:30.783

11 Can regular expressions be made unambiguous? 2010-11-07T08:38:21.233

11 Eilenberg's rational hiererchy of nonrational automata & languages — where is it now? 2012-02-22T14:41:27.497

10 Regular languages and the pumping lemma 2009-10-20T04:21:08.150

10 Is my definition of a context algebra new? 2010-01-29T21:52:37.117

10 Which Turing machines accept the language of trivial words in a finitely presented group? 2011-05-27T12:23:35.753

10 Computing the ordinal of a rational language well-partially-ordered by the subword relation 2016-04-24T05:15:38.623

9 Is there a formal notion of what we do when we 'Let X be ...'? 2010-04-05T00:43:10.797

9 palindromic subsequences 2011-01-23T20:09:53.547

9 Predicates of infinite arity 2011-02-22T17:38:17.000

9 Coherence and rewriting 2016-04-03T20:06:22.760

8 How to characterize a Self-avoiding path. 2010-10-08T21:51:33.447

8 Generating function of a regular language 2013-01-18T22:45:49.787

8 Is there a ``Ladner's Theorem" for the PH-vs-PSPACE scenario? 2015-03-04T20:37:23.333

7 Can you hide a letter without losing information? 2011-09-25T14:09:26.973

7 Constructing Metrics for specific Topological Spaces, and Refinements of the Cantor-Space in particular 2013-07-22T21:36:35.817

7 Is there a name for infinite words containing every finite words? 2014-05-18T08:58:27.340

7 Can ETCC/ETCS talk about 'size issues'? 2017-03-12T15:56:05.593

6 What assumptions and methodology do metaproofs of logic theorems use and employ? 2009-12-14T07:24:51.843

6 word problem in free Burnside groups (and other torsion groups) 2011-06-02T10:58:58.923

6 Growth zeta-functions of regular languages 2011-06-21T19:40:50.330

6 Generalising the adherence operator and its closure properties with regard to regular (rational) languages 2014-01-07T10:32:37.513

6 Separating infinite words sharing factors by automata 2014-01-15T11:02:47.897

6 Formal languages with non-unique interpretations of terms 2014-12-04T22:10:54.750

6 Is this variant of the balanced bracket language context free? 2015-02-03T00:17:27.867

6 Show that the positive existential theory is undecidable 2015-11-19T19:45:40.033

6 Neighbourhood of a word and Levenshtein distance 2016-05-11T14:14:44.537

6 What do we call this quantifier ("binder")? 2016-06-22T17:55:31.757

5 Proof formalization 2010-02-25T11:48:21.943

5 A special class of regular languages: "circular" languages. Is it known? 2011-01-11T14:54:42.263

5 Büchi automata with acceptance strategy 2012-05-15T14:51:05.440

5 How to work out a grammar if we know the language? 2013-04-02T22:42:04.553

5 List of open problems of formal languages 2013-06-16T10:32:52.347

5 Is it decidable whether the support of a rational $\mathbb{Z}$-series is a regular language? 2013-08-18T12:07:58.490

5 Ordering on words 2013-10-21T15:00:41.457

5 What prefix and factors determine a ultimately periodic word uniquely 2013-11-29T23:45:29.123

5 What exactly is a judgement? 2016-11-12T15:16:59.027

4 Context free grammar + functions = ? 2010-02-26T06:09:27.527

4 Semantics of Higher-Order Logics 2010-07-26T08:16:24.630

4 Are context-free languages with context-free complements necessarily deterministic context-free? 2012-02-21T21:46:23.483

4 Existential quantification over regular predicates 2012-06-28T16:14:42.830

4 Deciding equivalence of regular languages 2012-09-11T12:34:53.350

4 Properties of classical automata preserved in Büchi automata 2013-02-21T16:43:45.257

4 Progress on group languages characterizations 2013-10-14T10:47:26.433

4 Concatenation of strings 2013-11-02T10:48:31.820

4 Inherent ambiguity of the context-sensitive language $L = {a^ib^ic^id^je^jf^j \bigcap a^ib^jc^id^je^if^j} $ or $a^nb^nc^nd^ne^nf^n$ 2014-06-26T19:56:30.400

4 How can I catalog these generalized Collatz problems? 2017-12-25T20:14:01.893

3 Vocabulary on monoid periodicity 2010-07-17T02:53:47.857

3 To what extent MSO = WS1S, when adding relations? 2010-07-18T00:02:04.307

3 What is the relation between the number syntactic congruence classes, and the number of Nerode relation classes? 2010-07-22T04:53:17.483

3 'Closure' of CFLs under complementation and intersection 2011-01-10T14:46:23.897

3 density of formal language？ 2011-07-24T12:48:55.043

3 Finite variation and idempotent languages and automata 2011-08-02T22:50:15.140

3 Study of free monoids of the recursive S. Eilenberg. 2011-10-08T15:22:57.197

3 Certain type of regular languages 2012-03-13T10:58:09.323

3 L-systems and Sierpinski Triangle 2013-04-27T06:37:19.183

3 Subsets of $\omega$-regular lanuages accepted by automata with special acceptance condition 2013-10-28T13:01:26.047

3 The Kleene theorem 2013-11-24T14:16:33.600

3 Expressive power of first-order category theory 2014-02-27T10:44:52.473

3 Complexity of counting words of given length in regular or context-free language 2014-04-02T10:30:04.030

3 Are there any results on well-quasi-ordering of languages? 2014-08-12T23:15:11.397

3 How to get $\omega$-regular expression from buchi automaton 2016-04-03T12:43:09.980

2 Graph properties: definability and decidability 2011-01-08T23:31:47.937

2 Parsing of Stochastic Contex-Free Grammars (SCFGs) 2011-04-03T17:17:38.387

2 Given a PDA M such that L(M) is in DCFL construct a DPDA N such that L(N) = L(M) 2011-06-06T16:38:26.867

2 Are inference laws consistent? 2011-06-22T15:18:41.443

2 The intersection of Block Groups and R-trivial (finite) monoids 2011-08-09T12:50:57.910

2 When may function (meromorphic) be expanded as power series with coefficients of integers 2011-08-24T09:39:08.550

2 Question about $\omega$-regular languages 2012-03-16T21:50:16.063

2 Notation for ends of a string 2012-04-13T09:34:09.090

2 All properties of a mathematical object 2012-07-01T01:05:57.480

2 Is any CFL intersection,union of CFLs that are not inherently ambiguous? 2013-03-08T02:43:55.650

2 Generating function of factorable binary words 2013-07-28T10:49:56.343

2 Varieties of rational languages and (pseudo-)varieties of finite monoids, question regarding closure property 2013-10-07T14:44:30.957

2 Proof that the $\omega$-language consisting of all words containing every finite word as a factor is not rational/regular 2013-10-20T19:59:43.163

2 Representability of sets of infinite sequences sharing common prefixes and factors (i.e. infixes) 2013-12-06T15:00:31.190

2 Every infinite c.e.language is infinite or finite union of regular languages including at least one infinite regular language? 2014-02-18T02:02:28.907

2 Topology induced by context-free language 2017-01-28T13:55:34.557

1 A subset of all languages which is uncountable? 2009-11-03T00:20:19.357

1 Can I have an LL grammar for every deterministic context free language? 2010-07-13T16:36:13.567

1 A polynomial-time algorithm for deciding whether a language has a polynomial time algorithm 2010-08-13T19:22:46.823

1 Can a polynomial size CFG describe the finite language \{$w \pi(w)$ : $\pi(w)$ is fixed string permutation, $|w|=n$ is fixed\} over alphabet \{0,1\}? 2011-01-31T13:33:20.623

1 REGULAR TM is undecidable 2011-05-04T11:03:49.480

1 On the boundedness of linear representations of formal power series of languages. 2011-07-26T21:25:29.410

1 Translate a buchi automaton to LTL 2012-05-15T04:17:22.870

1 Is complement of LL(k) grammar context free? 2012-06-01T15:03:16.823

1 Satisfiability problem for FOL[<,R] 2012-06-29T15:28:45.947

1 Is there an recursively axiomatized system with infinitely many proofs for some propositions or a proposition 2013-06-23T00:25:44.107

1 Simple asymptotic combinatorics - how many words are there in a certain weight category? 2013-07-16T17:24:16.280