torsion-free rank

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• Torsion-free abelian groups of rank 1 — Infinitely generated abelian groups have very complex structure and are far less well understood than finitely generated abelian groups. Even torsion free abelian groups are vastly more varied in their characteristics than vector spaces. Torsion… …   Wikipedia

• Rank of an abelian group — In mathematics, the rank, or torsion free rank, of an abelian group measures how large a group is in terms of how large a vector space over the rational numbers one would need to contain it; or alternatively how large a free abelian group it can… …   Wikipedia

• Free abelian group — In abstract algebra, a free abelian group is an abelian group that has a basis in the sense that every element of the group can be written in one and only one way as a finite linear combination of elements of the basis, with integer coefficients …   Wikipedia

• Torsion (algebra) — In abstract algebra, the term torsion refers to a number of concepts related to elements of finite order in groups and to the failure of modules to be free. Definition Let G be a group. An element g of G is called a torsion element if g has… …   Wikipedia

• Torsion subgroup — In the theory of abelian groups, the torsion subgroup AT of an abelian group A is the subgroup of A consisting of all elements that have finite order. An abelian group A is called a torsion (or periodic) group if every element of A has finite… …   Wikipedia

• Rank of a group — For the dimension of the Cartan subgroup, see Rank of a Lie group In the mathematical subject of group theory, the rank of a group G , denoted rank( G ), can refer to the smallest cardinality of a generating set for G , that is:… …   Wikipedia

• Whitehead torsion — In mathematics, Whitehead torsion is an invariant of an h cobordism in a Whitehead group, that is important in simple homotopy theory and surgery theory. It is named for J. H. C. Whitehead.Whitehead torsionSuppose that W is an h cobordism from M… …   Wikipedia

• Locally cyclic group — In group theory, a locally cyclic group is a group ( G , *) in which every finitely generated subgroup is cyclic.ome facts*Every cyclic group is locally cyclic, and every locally cyclic group is abelian. *Every finitely generated locally cyclic… …   Wikipedia

• Abelian group — For other uses, see Abelian (disambiguation). Abelian group is also an archaic name for the symplectic group Concepts in group theory category of groups subgroups, normal subgroups group homomorphisms, kernel, image, quotient direct product,… …   Wikipedia

• Finitely generated abelian group — In abstract algebra, an abelian group ( G ,+) is called finitely generated if there exist finitely many elements x 1,..., x s in G such that every x in G can be written in the form : x = n 1 x 1 + n 2 x 2 + ... + n s x s with integers n 1,..., n… …   Wikipedia

• Finitely-generated abelian group — In abstract algebra, an abelian group (G,+) is called finitely generated if there exist finitely many elements x1,...,xs in G such that every x in G can be written in the form x = n1x1 + n2x2 + ... + nsxs with integers n1,...,ns. In this case, we …   Wikipedia