On -categoricity and the theory of trees
On 2nd order intuitionistic propositional calculus with full comprehension.
On a connection between the word problem and decidability of the equational theory.
On a Problem of Boone.
On a unification problem related to Kreisel's conjecture
On cardinalities of algebras of formulas for -categorical theories
On decidability of one class of boolean formulas
On effective speed-up and long proofs of trivial theorems in formal theories
On knowledge games.
We give a formalization of the ?knowledge games? which allows to study their decidability and convergence as a problem of mathematics. Our approach is based on a metalemma analogous to those of Von Neumann and Morgenstern at the beginning of Game Theory. We are led to definitions which characterize the knowledge games as objects is standard set theory. We then study rigorously the most classical knowledge games and, although we also prove that the ?common knowledge? in these games may be incomputable,...
On the Algebraic Complexity of Sets of Functions
On the decidability of p', p'' and p''*.
On the decidability of semigroup freeness∗
This paper deals with the decidability of semigroup freeness. More precisely, the freeness problem over a semigroup S is defined as: given a finite subset X ⊆ S, decide whether each element of S has at most one factorization over X. To date, the decidabilities of the following two freeness problems have been closely examined. In 1953, Sardinas and Patterson proposed a now famous algorithm for the freeness problem over the free monoids....
On the decidability of semigroup freeness
This paper deals with the decidability of semigroup freeness. More precisely, the freeness problem over a semigroup S is defined as: given a finite subset X ⊆ S, decide whether each element of S has at most one factorization over X. To date, the decidabilities of the following two freeness problems have been closely examined. In 1953, Sardinas and Patterson proposed a now famous algorithm for the freeness problem over the free monoids. In 1991, Klarner, Birget and Satterfield proved the undecidability...
On the decidability of semigroup freeness∗
This paper deals with the decidability of semigroup freeness. More precisely, the freeness problem over a semigroup S is defined as: given a finite subset X ⊆ S, decide whether each element of S has at most one factorization over X. To date, the decidabilities of the following two freeness problems have been closely examined. In 1953, Sardinas and Patterson proposed a now famous algorithm for the freeness problem over the free monoids....
On the decidability of the theory of linear orderings with generalized quantifiers
On the elementary theory of inductive order.
On The Greatest Congruence Of Relations
On the greatest congruence of relations.
On the restricted equivalence for subclasses of propositional logic
On universal theories of metabelian groups and the Shmel'kin embedding.