# 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. - published version (13p)

Bib entry

@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} }