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math.LO2005
Disjoint Non-Free Subgoups of Abelian Groups
Andreas Blass, Saharon Shelah
Let G be an abelian group and let lambda be the smallest rank of any group whose direct sum with a free group is isomorphic to G. If lambda is uncountable, then G has lambda pairwi…
math.LO2005
Ultrafilters and partial products of infinite cyclic groups
Andreas Blass, Saharon Shelah
We consider, for infinite cardinals kappa and alpha <= kappa^+, the group Pi(kappa,< alpha) of sequences of integers, of length kappa, with non-zero entries in fewer than alpha pos…
math.LO2001
On Polynomial Time Computation Over Unordered Structures
Andreas Blass, Yuri Gurevich, Saharon Shelah
This paper is motivated by the question whether there exists a logic capturing polynomial time computation over unordered structures. We consider several algorithmic problems near…