On a Geometric Problem of Zigzags. - Vesa Halava; Tero Harju; Lucian Ilie (Inf. Process. Lett., 1997)

Languages Accepted by Integer Weighted Finite Automata. - Vesa Halava; Tero Harju (Jewels are Forever, 1999)

Generalized PCP Is Decidable for Marked Morphisms. - Vesa Halava; Tero Harju; Mika Hirvensalo (FCT, 1999)

Decidability and Undecidability of Marked PCP. - Vesa Halava; Mika Hirvensalo; Ronald de Wolf (STACS, 1999)

Undecidability in Integer Weighted Finite Automata. - Vesa Halava; Tero Harju (Fundam. Informaticae, 1999)

Undecidability of the equivalence of finite substitutions on regular language. - Vesa Halava; Tero Harju (RAIRO Theor. Informatics Appl., 1999)

Generalized Post Correspondence Problem for Marked Morphisms. - Vesa Halava; Tero Harju; Mika Hirvensalo (Int. J. Algebra Comput., 2000)

Periods and Binary Words. - Vesa Halava; Tero Harju; Lucian Ilie (J. Comb. Theory A, 2000)

An Undecidability Result Concerning Periodic Morphisms. - Vesa Halava; Tero Harju (Developments in Language Theory, 2001)

Some New Results on Post Correspondence Problem and Its Modifications. - Vesa Halava; Tero Harju (Bull. EATCS, 2001)

Mortality in Matrix Semigroups. - Vesa Halava; Tero Harju (Am. Math. Mon., 2001)

Marked PCP is decidable. - Vesa Halava; Mika Hirvensalo; Ronald de Wolf (Theor. Comput. Sci., 2001)

Infinite Solutions of Marked Post Correspondence Problem. - Vesa Halava; Tero Harju (Formal and Natural Computing, 2002)

Binary (generalized) Post Correspondence Problem. - Vesa Halava; Tero Harju; Mika Hirvensalo (Theor. Comput. Sci., 2002)

Languages Defined by Generalized Equality Sets. - Vesa Halava; Tero Harju; Hendrik Jan Hoogeboom; Michel Latteux (FCT, 2003)

Decidability of the binary infinite Post Correspondence Problem. - Vesa Halava; Tero Harju; Juhani Karhumäki (Discret. Appl. Math., 2003)

Integer Weighted Finite Automata, Matrices, and Formal Power Series over Laurent Polynomials. - Vesa Halava (Theory Is Forever, 2004)

Undecidability in matrices over Laurent polynomials. - Vesa Halava; Tero Harju (Adv. Appl. Math., 2004)

Valence Languages Generated by Equality Sets. - Vesa Halava; Tero Harju; Hendrik Jan Hoogeboom; Michel Latteux (J. Autom. Lang. Comb., 2004)

Representation of Regular Languages by Equality Sets. - Vesa Halava; Tero Harju; Michel Latteux (Bull. EATCS, 2005)

Equality sets of prefix morphisms and regular star languages. - Vesa Halava; Tero Harju; Michel Latteux (Inf. Process. Lett., 2005)

Equality sets for recursively enumerable languages. - Vesa Halava; Tero Harju; Hendrik Jan Hoogeboom; Michel Latteux (RAIRO Theor. Informatics Appl., 2005)

Positivity of second order linear recurrent sequences. - Vesa Halava; Tero Harju; Mika Hirvensalo (Discret. Appl. Math., 2006)

Undecidability in omega-Regular Languages. - Vesa Halava; Tero Harju; Juhani Karhumäki (Fundam. Informaticae, 2006)

Undecidability of infinite post correspondence problem for instances of Size 9. - Vesa Halava; Tero Harju (RAIRO Theor. Informatics Appl., 2006)

Improved matrix pair undecidability results. - Vesa Halava; Mika Hirvensalo (Acta Informatica, 2007)

Undecidability Bounds for Integer Matrices Using Claus Instances. - Vesa Halava; Tero Harju; Mika Hirvensalo (Int. J. Found. Comput. Sci., 2007)

The Structure of Infinite Solutions of Marked and Binary Post Correspondence Problems. - Vesa Halava; Tero Harju; Juhani Karhumäki (Theory Comput. Syst., 2007)

Relational codes of words. - Vesa Halava; Tero Harju; Tomi Kärki (Theor. Comput. Sci., 2007)

Extension of the decidability of the marked PCP to instances with unique blocks. - Vesa Halava; Tero Harju; Juhani Karhumäki; Michel Latteux (Theor. Comput. Sci., 2007)

Interaction Properties of Relational Periods. - Tomi Kärki; Tero Harju; Vesa Halava (Discret. Math. Theor. Comput. Sci., 2008)

Matrix Equations and Hilbert's Tenth Problem. - Paul Bell; Vesa Halava; Tero Harju; Juhani Karhumäki; Igor Potapov (Int. J. Algebra Comput., 2008)

Preface. - Vesa Halava; Igor Potapov (Int. J. Found. Comput. Sci., 2008)

Post Correspondence Problem for short words. - Vesa Halava; Tero Harju; Mika Hirvensalo; Juhani Karhumäki (Inf. Process. Lett., 2008)

Square-free partial words. - Vesa Halava; Tero Harju; Tomi Kärki (Inf. Process. Lett., 2008)

The theorem of Fine and Wilf for relational periods. - Vesa Halava; Tero Harju; Tomi Kärki (RAIRO Theor. Informatics Appl., 2009)

Overlap-freeness in infinite partial words. - Vesa Halava; Tero Harju; Tomi Kärki; Patrice Séébold (Theor. Comput. Sci., 2009)

On post correspondence problem for letter monotonic languages. - Vesa Halava; Jarkko Kari; Yuri V. Matiyasevich (Theor. Comput. Sci., 2009)

On the Periodicity of Morphic Words. - Vesa Halava; Tero Harju; Tomi Kärki; Michel Rigo (Developments in Language Theory, 2010)

On the Joint Spectral Radius for Bounded Matrix Languages. - Paul Bell; Vesa Halava; Mika Hirvensalo (RP, 2010)

On the number of squares in partial words. - Vesa Halava; Tero Harju; Tomi Kärki (RAIRO Theor. Informatics Appl., 2010)

A new proof for the decidability of D0L ultimate periodicity - Vesa Halava; Tero Harju; Tomi Kärki (WORDS, 2011)

Reduction Tree of the Binary Generalized Post Correspondence Problem. - Vesa Halava; Stepan Holub (Int. J. Found. Comput. Sci., 2011)

Words, Graphs, Automata, and Languages; Special Issue Honoring the 60th Birthday of Professor Tero Harju. - Vesa Halava; Juhani Karhumäki; Dirk Nowotka; Grzegorz Rozenberg (Fundam. Informaticae, 2012)

Deterministic Semi-Thue Systems and Variants of Post Correspondence Problem. - Vesa Halava (WORDS, 2013)

New proof for the undecidability of the circular PCP. - Vesa Halava; Tero Harju (Acta Informatica, 2013)

Decision Problems for Probabilistic Finite Automata on Bounded Languages. - Paul C. Bell; Vesa Halava; Mika Hirvensalo (Fundam. Informaticae, 2013)

Tighter Undecidability Bounds for Matrix Mortality, Zero-in-the-Corner Problems, and More. - Julien Cassaigne; Vesa Halava; Tero Harju; François Nicolas (CoRR, 2014)

Another proof of undecidability for the correspondence decision problem - Had I been Emil Post. - Vesa Halava (CoRR, 2014)

On Undecidability of Counter Reachability Games in Dimension One. - Vesa Halava; Reino Niskanen; Igor Potapov (CoRR, 2014)

Preface. - Vesa Halava; Juhani Karhumäki; Yuri V. Matiyasevich (Fundam. Informaticae, 2014)

On Robot Games of Degree Two. - Vesa Halava; Reino Niskanen; Igor Potapov (LATA, 2015)

On the n-permutation Post Correspondence Problem. - Mari Ernvall; Vesa Halava; Tero Harju (Theor. Comput. Sci., 2015)

A New Proof for Undecidability of the Bi-Infinite Post Correspondence Problem. - Vesa Halava; Tero Harju; Esa Sahla (Fundam. Informaticae, 2017)

Small Semi-Thue System Universal with Respect to the Termination Problem. - Vesa Halava; Yuri V. Matiyasevich; Reino Niskanen (Fundam. Informaticae, 2017)

Weighted automata on infinite words in the context of Attacker-Defender games. - Vesa Halava; Tero Harju; Reino Niskanen; Igor Potapov (Inf. Comput., 2017)

Walks on tilings of polygons. - Vesa Halava; Tero Harju (Theor. Comput. Sci., 2017)

Perface. - Vesa Halava; Juhani Karhumäki; Yuri V. Matiyasevich; Mikhail V. Volkov 001 (Fundam. Informaticae, 2018)

On fixed points of rational transductions. - Vesa Halava; Tero Harju; Esa Sahla (Theor. Comput. Sci., 2018)

On the Steps of Emil Post: from Normal Systems to the Correspondence Decision Problem. - Vesa Halava; Tero Harju (Acta Cybern., 2020)

On Shuffling a Word with its Letter-to-Letter Substitution. - Vesa Halava; Tero Harju; Esa Sahla (Fundam. Informaticae, 2020)

The Conjugate Post Correspondence Problem. - Vesa Halava; Tero Harju; Esa Sahla (CoRR, 2021)

Undecidability in Finite Transducers, Defense Systems and Finite Substitutions. - Vesa Halava (CoRR, 2021)

A recursive function coding number theoretic functions. - Vesa Halava; Tero Harju; Teemu Pirttimäki (CoRR, 2022)

Integer Weighted Automata on Infinite Words. - Vesa Halava; Tero Harju; Reino Niskanen; Igor Potapov (Int. J. Found. Comput. Sci., 2023)

On bi-infinite and conjugate post correspondence problems. - Olivier Finkel; Vesa Halava; Tero Harju; Esa Sahla (RAIRO Theor. Informatics Appl., 2023)

Decision Problems on Copying and Shuffling. - Vesa Halava; Tero Harju; Dirk Nowotka; Esa Sahla (Fundam. Informaticae, 2024)

Preface. - Vesa Halava; Jarkko Kari; Tero Laihonen (Fundam. Informaticae, 2024)

Binary Generalized PCP for Two Periodic Morphisms is Decidable in Polynomial Time. - Vesa Halava; Stepan Holub (Int. J. Found. Comput. Sci., 2024)

On simulating Turing machines with matrix semigroups with integrality tests. - Vesa Halava; Reino Niskanen (Theor. Comput. Sci., 2024)