Über einge Eigenschaften der Kommutatoren der symmetrischen Halbgruppe.
Un problème combinatoire de la théorie des codes
Undecidable varieties with solvable word problems. II.
Undecidable varieties with solvable word problems. III (a semigroup variety).
Une Condition Finitude Pour les Semi-groupes
Uniformly synchronous codes.
Union and symmetry preserving homomorphisms of semigroups of closed relations.
Unique prime factorization in a partial semigroup of matrix-polynomials
We establish a unique factorization result into irreducibel elements in the partial semigroup of 2 × 2-matrices with entries in K[x] whose determinant is equal to 1, where K is a field, and where multiplication is defined as the usual matrix-multiplication if the degrees of the factors add up. This investigation is motivated by a result on matrices of entire functions.