Vesa Halava
vesa.halava@utu.fi +358 29 450 4304 +358 50 320 6267 Vesilinnantie 5 Turku : 368 Contact by email. |
computability; automata and formal languages; logic; combinatorics on words
I am a Professor of Discrete Mathematics and Theoretical Computer Science.
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.
I teach two course in Logic, basic course and advanced level course. I also teach Analysis I for (the first year) students of mathematics.
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- Undecidability of infinite post correspondence problem for instances of size 9 (2006)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
- Equality sets for recursively enumerable languages (2005)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
- Equality sets of prefix morphisms and regular star languages (2005)
- Information Processing Letters
- Integer weighted finite automata, matrices, and formal power series-over Laurent polynomials (2004)
- Lecture Notes in Computer Science
- Undecidability in matrices over Laurent polynomials\ (2004)
- Advances in Applied Mathematics
- Decidability of the binary infinite post correspondence problem (2003)
- Discrete Applied Mathematics
- Languages defined by generalized equality sets (2003)
- Lecture Notes in Computer Science
- An undecidability result concerning periodic morphisms (2002)
- Lecture Notes in Computer Science
- Binary (generalized) Post Correspondence Problem (2002)
- Theoretical Computer Science
- Marked PCP is decidable (2001)
- Theoretical Computer Science
- Mortality in matrix semigroups (2001)
- American Mathematical Monthly
- Generalized post correspondence problem for marked morphisms (2000)
- International Journal of Algebra and Computation
- Periods and binary words (2000)
- Journal of Combinatorial Theory, Series A
- Decidability and undecidability of marked PCP (1999)
- Lecture Notes in Computer Science
- Decidability and undecidability of marked PCP (1999) 16th Annual Symposium on Theoretical Aspects of Computer Science Halava V, Hirvensalo. M, de Wolf R
- Generalized PCP is decidable for marked morphisms (1999)
- Lecture Notes in Computer Science
- Undecidability of the equivalence of finite substitutions on regular language (1999)
- RAIRO: Informatique Théorique et Applications / RAIRO: Theoretical Informatics and Applications
- On a geometric problem of zigzags (1997)
- Information Processing Letters
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