On the congruence-subgroup problem for some anisotropic algebraic groups over number fields.
On the conjugacy problem for Carter subgroups.
On the Conjugacy Problem for Knot Groups.
On the Conjugacy Problem in a Free Product with Commuting Subgroups.
On the conjugate type vector and the structure of a normal subgroup
Let be a normal subgroup of a group . The structure of is given when the -conjugacy class sizes of is a set of a special kind. In fact, we give the structure of a normal subgroup under the assumption that the set of -conjugacy class sizes of is , where , and are distinct primes for , .
On the connectedness of the locus of real Riemann surfaces.
On the construction of bisimple orthodox semigroups.
On the construction of factorial designs using abelian group theory
On the construction of non-congruence subgroups
On the Construction of Primitive Elements in Field Extensions.
On the construction of some semigroups
On the converse of a theorem of Harte and Mbekhta: Erratum to "On generalized inverses in C*-algebras"
We prove that the converse of Theorem 9 in "On generalized inverses in C*-algebras" by Harte and Mbekhta (Studia Math. 103 (1992)) is indeed true.
On the critical pair theory in ℤ/pℤ
On the Cuspidal Cohomology of the Bianchi Modular Groups.
On the cut number of a 3-manifold.
On the cut point conjecture.
On the cyclic subgroup separability of free products of two groups with amalgamated subgroup.
On the Davenport constant and group algebras
For a finite abelian group G and a splitting field K of G, let (G,K) denote the largest integer l ∈ ℕ for which there is a sequence over G such that for all . If (G) denotes the Davenport constant of G, then there is the straightforward inequality (G) - 1 ≤ (G,K). Equality holds for a variety of groups, and a conjecture of W. Gao et al. states that equality holds for all groups. We offer further groups for which equality holds, but we also give the first examples of groups G for which (G) -...
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...