Sh:426

• Eklof, P. C., Mekler, A. H., & Shelah, S. (1993). On coherent systems of projections for \aleph_1-separable groups. Comm. Algebra, 21(1), 343–353. arXiv: math/9308213 DOI: 10.1080/00927879208824564 MR: 1194564
• Abstract:
  It is proved consistent with either CH or the negation of CH that there is an \aleph_1-separable group of cardinality \aleph_1 which does not have a coherent system of projections. It had previously been shown that it is consistent with \negCH that every \aleph_1-separable group of cardinality \aleph_1 does have a coherent system of projections.
• Version 1993-08-26_10 (11p) published version (13p)

@article{Sh:426,
 author = {Eklof, Paul C. and Mekler, Alan H. and Shelah, Saharon},
 title = {{On coherent systems of projections for $\aleph_1$-separable groups}},
 journal = {Comm. Algebra},
 fjournal = {Communications in Algebra},
 volume = {21},
 number = {1},
 year = {1993},
 pages = {343--353},
 issn = {0092-7872},
 mrnumber = {1194564},
 mrclass = {20K20},
 doi = {10.1080/00927879208824564},
 note = {\href{https://arxiv.org/abs/math/9308213}{arXiv: math/9308213}},
 arxiv_number = {math/9308213}
}