On free pseudo-complemented and relatively pseudo-complemented semi-lattices
On Some Classes Of Unrecognizable Properties Of Groups
On some classes of unrecognizable properties of groups.
On the complexity of the word problem for finitely presented commutative semigroups.
On the Conjugacy Problem for Knot Groups.
Positive eigenvalues and two-letter generalized words.
Problèmes d 'associativité des monoïdes et problèmes des mots pour les groupes
Solving word equations
Some Algebraic Properties of Machine Poset of Infinite Words
The complexity of infinite words is considered from the point of view of a transformation with a Mealy machine that is the simplest model of a finite automaton transducer. We are mostly interested in algebraic properties of the underlying partially ordered set. Results considered with the existence of supremum, infimum, antichains, chains and density aspects are investigated.
Some Recent Results on Squarefree Words
String Matching And Algorithmic Problems In Free Groups.
The conjugacy problem for groups, and Higman embeddings.
Two decidable Markov properties over a class of solvable groups.
Über die darstellbarkeit des syntaktischen monoïdes kontextfreier sprachen
Undecidability of infinite post correspondence problem for instances of size 8
The infinite Post Correspondence Problem (ωPCP) was shown to be undecidable by Ruohonen (1985) in general. Blondel and Canterini [Theory Comput. Syst. 36 (2003) 231–245] showed that ωPCP is undecidable for domain alphabets of size 105, Halava and Harju [RAIRO–Theor. Inf. Appl. 40 (2006) 551–557] showed that ωPCP is undecidable for domain alphabets of size 9. By designing a special coding, we delete a letter from Halava and Harju’s construction. So we prove that ωPCP is undecidable for domain alphabets...
Undecidability of infinite post correspondence problem for instances of size 8
The infinite Post Correspondence Problem (ωPCP) was shown to be undecidable by Ruohonen (1985) in general. Blondel and Canterini [Theory Comput. Syst. 36 (2003) 231–245] showed that ωPCP is undecidable for domain alphabets of size 105, Halava and Harju [RAIRO–Theor. Inf. Appl. 40 (2006) 551–557] showed that ωPCP is undecidable for domain alphabets of size 9. By designing a special coding, we delete a letter from Halava and Harju’s construction. So we prove that ωPCP is undecidable for domain alphabets...
Undecidability of infinite post correspondence problem for instances of Size 9
In the infinite Post Correspondence Problem an instance (h,g) consists of two morphisms h and g, and the problem is to determine whether or not there exists an infinite word ω such that h(ω) = g(ω). This problem was shown to be undecidable by Ruohonen (1985) in general. Recently Blondel and Canterini (Theory Comput. Syst.36 (2003) 231–245) showed that this problem is undecidable for domain alphabets of size 105. Here we give a proof that the infinite Post Correspondence Problem is undecidable...
Undecidable varieties with solvable word problems. II.
Undecidable varieties with solvable word problems. III (a semigroup variety).
Unification for nilpotent groups of class 2.