Displaying similar documents to “A non-commutative free algebra of rank 0”

Conjugacy pinched and cyclically pinched one-relator groups.

Benjamin Fine, Gerhard Rosenberger, Michael Stille (1997)

Revista Matemática de la Universidad Complutense de Madrid

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Here we consider two classes of torsion-free one-relator groups which have proved quite amenable to study-the cyclically pinched one-relator groups and the conjugacy pinched one-relator groups. The former is the class of groups which are free products of free groups with cyclic amalgamations while the latter is the class of HNN extensions of free groups with cyclic associated subgroups. Both are generalizations of surface groups. We compare and contrast results in these classes relative...

Equivalential algebras with conjunction on the regular elements

Sławomir Przybyło (2021)

Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica

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We introduce the definition of the three-element equivalential algebra R with conjunction on the regular elements. We study the variety generated by R and prove the Representation Theorem. Then, we construct the finitely generated free algebras and compute the free spectra in this variety.

On free subgroups of units in quaternion algebras

Jan Krempa (2001)

Colloquium Mathematicae

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It is well known that for the ring H(ℤ) of integral quaternions the unit group U(H(ℤ) is finite. On the other hand, for the rational quaternion algebra H(ℚ), its unit group is infinite and even contains a nontrivial free subgroup. In this note (see Theorem 1.5 and Corollary 2.6) we find all intermediate rings ℤ ⊂ A ⊆ ℚ such that the group of units U(H(A)) of quaternions over A contains a nontrivial free subgroup. In each case we indicate such a subgroup explicitly. We do our best to...