Torsion points of elliptic curves over large algebraic extensions of finitely generated fields

The following Theorem is proved:Let K be a finitely generated field over its prime field. Then, for almost all e-tuples (σ)=(σ ₁, …,σ _e)of elements of the abstract Galois group G(K)of K we have:

1. If e=1,then E _tor(K(σ))is infinite. Morover, there exist infinitely many primes l such that E(K(σ))contains points of order l.
2. If e≧2,then E _tor(K(σ))is finite.
3. If e≧1,then for every prime l, the group E(K(σ))contains only finitely many points of an l-power order.

HereK(σ) is the fixed field in the algebraic closureK ofK, ofσ ₁, …,σ _e, and “almost all” is meant in the sense of the Haar measure ofG(K).     

Monomorphisms of finitely generated free groups have finitely generated equalizers

Summary The authors' approach to Gersten's graphical model of an automorphism is generalized to prove the theorem of the title, resolving a conjecture of Stallings.     

Tits geometries and parabolic systems in finitely generated groups II

Mathematische Zeitschrift -     

A pure subalgebra of a finitely generated algebra is finitely generated

We prove the following. Let be a Noetherian commutative ring, a finitely generated -algebra, and a pure -subalgebra of . Then is finitely generated over .

     

Factorization in finitely generated domains

Let D be a Noetherian domain. Then it is well known that D is atomic, i.e. every non-zero non-unit a∈D possesses a factorization

     

Intersections of finitely generated clones

We answer negatively the following question asked by Stanley Burris: Is the intersection of two finitely generated clones always finitely generated?     

A finitely generated just-infinite profinite branch group which is not positively finitely generated

We construct a finitely generated profinite branch group which is just-infinite and not positively finitely generated.     

Polynomial cycles in finitely generated domains

LetR be a finitely generated domain of zero characteristics, and letN be a given integer. We show that the lengths of all cycles of polynomial mappingsR ^NR ^N defined overR are bounded by a number depending only onR andN.The work of the second author has been supported by the KBN-grant 2-1037-91-01.     

Nontrivial identities in finitely generated semigroups

Ivanovo. Translated from Sibirskii Matematicheskii Zhurnal, Vol. 30, No. 3, pp. 191–197, May–June, 1989.     

On finitely generated multiplication modules

We shall prove that if M is a finitely generated multiplication module and Ann(M) is a finitely generated ideal of R, then there exists a distributive lattice M such that Spec(M) with Zariski topology is homeomorphic to Spec(M) to Stone topology. Finally we shall give a characterization of finitely generated multiplication R-modules M such that Ann(M) is a finitely generated ideal of R.     

On finitely generated projective modules

It is shown that the set End _A (M) is a Waelbroeck algebra, for every topological Waelbroeck algebraA and for every finitely generated projectiveA-moduleM. The research of Mart Abel was supported by Greek State Scholarship Foundation and Estonian Science Foundation grant 6205.     

On finitely generated idempotent semigroups

We give two short proofs of the well-known fact that every finitely generated idempotent semigroup is finite.     

Decomposing finitely generated torsion modules

Let R be a commutative ring and let F be a filter of ideals of R. We give three characterizations of the rings with the property that all finitely generated F pretorsion R modules decompose into a direct sum of cyclic R submodules. One of these characterizations involves decomposing the filter F into a product of subfilters. This filter decomposition is shown to be unique, and is used to characterize several other ring properties relative to the filter of ideals.     

Strongly taut finitely generated monoids

A strongly taut monoid is a monoid in which all the powers of any element of the monoid have the same elasticity, that is, the ratio between the maximum and the minimum length of the factorizations of an element remains unchanged under powers. We give a procedure to determine if a finitely generated commutative monoid is strongly taut.