Halava, Vesa

name

• Halava, Vesa

Authored works

• An undecidability result concerning periodic morphisms
• Binary (generalized) post correspondence problem is in P
• Characterization of infinite solutions of marked and binary post correspondence problems
• Decidability and undecidability of marked PCP
• Decidability of binary infinite post correspondence problem
• Decidable and undecidable problems in matrix theory
• Defect theorems with compatibility relation
• Equality sets of prefix morphisms and regular star languages
• Finite substitutions and integer weighted finite automata
• Generalized PCP is decidable for marked morphisms
• Improved matrix pair undecidability results
• Infinite solutions of marked post correspondence problem
• Integer weighted finite automata, matrices and formal power series over Laurent polynomials
• Interaction properties of relational periods
• Languages accepted by integer weighted finite automata
• On a geometric problem of Zig-Zags
• On marked post correspondence problem
• On Markov's undecidability theorem for integer matrices
• Periods and binary words
• Positivity of second order linear recurrent sequences
• Relational codes of words
• Some new results on post correspondence problem and its modifications
• The post correspondence problem for marked morphisms
• The theorem of Fine and Wilf for relational periods
• Undecidability bounds for integer matrices using Claus instances
• Undecidability in [omega]-regular languages
• Undecidability in integer weighted finite automata
• Undecidability in matrices over Laurent polynomials
• Undecidability of infinite Post Correspondence Problem for instances of size 9
• Undecidability of the equivalence of finite substitutions on regular language

Works contributed to

• (G)PCP for words of length at most two
• Equality sets for recursively enumerable languages
• Languages defined by generalized equality sets
• Post correspondence problem for morphisms with unique blocks
• Proceedings of the second Russian Finnish Symposium on Discrete Mathematics 2012
• Skolem's problem : on the border between decidability and undecidability
• Valence languages generated by equality sets

Works about Halava, Vesa