On universal locally finite groups

We deal with the question of existence of a universal object in the category of universal locally finite groups; the answer is negative for many uncountable cardinalities; for example, for 2ℵ0, and assuming G.C.H. for every cardinal whose confinality is >ℵ0. However, if λ>κ when κ is strongly compact and of λ=ℵ0, then there exists a universal locally finite group of cardinality λ. The idea is to use the failure of the amalgamation property in a strong sense. We shall also prove the failure of the amalgamation property for universal locally finite groups by transferring the kind of failure of the amalgamation property from LF into ULF.

[1]  Saharon Shelah,et al.  Existentially closed structures in the power of the continuum , 1984, Ann. Pure Appl. Log..

[2]  B. A. F. Wehrfritz,et al.  Locally finite groups , 1973 .

[3]  Saharon Shelah Categoricity in ℵ1 of sentences in $$L_{\omega _1 ,\omega } (Q)$$ , 1975 .

[4]  S. Shelah,et al.  Uncountable universal locally finite groups , 1976 .

[5]  P. Hall,et al.  Some Constructions for Locally Finite Groups , 1959 .

[6]  B. Neumann,et al.  On amalgams of periodic groups , 1960, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.