Displaying similar documents to “On countable extensions of primary abelian groups”

A note on the countable extensions of separable p ω + n -projective abelian p -groups

Peter Vassilev Danchev (2006)

Archivum Mathematicum

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It is proved that if G is a pure p ω + n -projective subgroup of the separable abelian p -group A for n ∈ N ∪ { 0 } such that | A / G | ≤ ℵ 0 , then A is p ω + n -projective as well. This generalizes results due to Irwin-Snabb-Cutler (CommentṀathU̇nivṠtṖauli, 1986) and the author (Arch. Math. (Brno), 2005).

Notes on countable extensions of  p ω + n -projectives

Peter Vassilev Danchev (2008)

Archivum Mathematicum

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We prove that if G is an Abelian p -group of length not exceeding ω and H is its p ω + n -projective subgroup for n ∈ ℕ ∪ { 0 } such that G / H is countable, then G is also p ω + n -projective. This enlarges results of ours in (Arch. Math. (Brno), 2005, 2006 and 2007) as well as a classical result due to Wallace (J. Algebra, 1971).

On extensions of primary almost totally projective abelian groups

Peter Vassilev Danchev (2008)

Mathematica Bohemica

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Suppose G is a subgroup of the reduced abelian p -group A . The following two dual results are proved: ( * ) If A / G is countable and G is an almost totally projective group, then A is an almost totally projective group. ( * * ) If G is countable and nice in A such that A / G is an almost totally projective group, then A is an almost totally projective group. These results somewhat strengthen theorems due to Wallace (J. Algebra, 1971) and Hill (Comment. Math. Univ. Carol., 1995), respectively. ...