Vesa Halava
vesa.halava@utu.fi +358 29 450 4304 +358 50 320 6267 Vesilinnantie 5 Turku Office: 368 Contact by email. ORCID identifier: https://orcid.org/0000-0003-3633-4902 |
Areas of expertise
computability; automata and formal languages; logic; combinatorics on words
computability; automata and formal languages; logic; combinatorics on words
Biography
I am a Professor of Discrete Mathematics and Theoretical Computer Science.
Research
My main field of research is in the field of Computability, more precisely on undecidable problems in automata and formal langauges and in the semigroups generated by integer matrices. Recently, I have also focused on the Foundations of Computation and related issues in the Foundations of Mathematics -- in Logic and Set Theory. I have also published articles in Combinatorics on Words.
Teaching
I teach two course in Logic, basic course and advanced level course. I also teach Analysis I for (the first year) students of mathematics.
Publications 
4 of 4
- Undecidability of infinite post correspondence problem for instances of size 9 (2006)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
(A1 Refereed original research article in a scientific journal) - Equality sets for recursively enumerable languages (2005)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
(A1 Refereed original research article in a scientific journal) - Equality sets of prefix morphisms and regular star languages (2005)
- Information Processing Letters
(A1 Refereed original research article in a scientific journal) - Integer weighted finite automata, matrices, and formal power series-over Laurent polynomials (2004)
- Lecture Notes in Computer Science
(A3 Refereed book chapter or chapter in a compilation book) - Undecidability in matrices over Laurent polynomials\ (2004)
- Advances in Applied Mathematics
(A1 Refereed original research article in a scientific journal) - Decidability of the binary infinite post correspondence problem (2003)
- Discrete Applied Mathematics
(A1 Refereed original research article in a scientific journal) - Languages defined by generalized equality sets (2003)
- Lecture Notes in Computer Science
(A1 Refereed original research article in a scientific journal) - An undecidability result concerning periodic morphisms (2002)
- Lecture Notes in Computer Science
(A4 Refereed article in a conference publication ) - Binary (generalized) Post Correspondence Problem (2002)
- Theoretical Computer Science
(A1 Refereed original research article in a scientific journal) - Marked PCP is decidable (2001)
- Theoretical Computer Science
(A1 Refereed original research article in a scientific journal) - Mortality in matrix semigroups (2001)
- American Mathematical Monthly
(A1 Refereed original research article in a scientific journal) - Generalized post correspondence problem for marked morphisms (2000)
- International Journal of Algebra and Computation
(A1 Refereed original research article in a scientific journal) - Periods and binary words (2000)
- Journal of Combinatorial Theory, Series A
(A1 Refereed original research article in a scientific journal) - Decidability and undecidability of marked PCP (1999)
- Lecture Notes in Computer Science
(A4 Refereed article in a conference publication ) - Decidability and undecidability of marked PCP (1999) 16th Annual Symposium on Theoretical Aspects of Computer Science Halava V, Hirvensalo. M, de Wolf R
(A4 Refereed article in a conference publication ) - Generalized PCP is decidable for marked morphisms (1999)
- Lecture Notes in Computer Science
(A1 Refereed original research article in a scientific journal) - Undecidability of the equivalence of finite substitutions on regular language (1999)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
(A1 Refereed original research article in a scientific journal) - On a geometric problem of zigzags (1997)
- Information Processing Letters
(A1 Refereed original research article in a scientific journal)
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