Šaroch, Jan On the nontrivial solvability of systems of homogeneous linear equations over \(\mathbb{Z}\) in ZFC. (English) Zbl 07285998 Commentat. Math. Univ. Carol. 61, No. 2, 155-164 (2020). Summary: Motivated by the paper by H. Herrlich and E. Tachtsis [Commentat. Math. Univ. Carol. 58, No. 2, 241–260 (2017; Zbl 1463.03017)] we investigate in ZFC the following compactness question: for which uncountable cardinals \(\kappa\), an arbitrary nonempty system \(S\) of homogeneous \(\mathbb{Z}\)-linear equations is nontrivially solvable in \(\mathbb{Z}\) provided that each of its subsystems of cardinality less than \(\kappa\) is nontrivially solvable in \(\mathbb{Z}\)? MSC: 08A45 Equational compactness 13C10 Projective and free modules and ideals in commutative rings 20K30 Automorphisms, homomorphisms, endomorphisms, etc. for abelian groups 03E35 Consistency and independence results 03E55 Large cardinals Keywords:homogeneous \(\mathbb{Z}\)-linear equation; \(\kappa\)-free group; \(\mathcal L_{\omega_1\omega}\)-compact cardinal Citations:Zbl 1463.03017 PDF BibTeX XML Cite \textit{J. Šaroch}, Commentat. Math. Univ. Carol. 61, No. 2, 155--164 (2020; Zbl 07285998) Full Text: DOI arXiv OpenURL References: [1] Bagaria J.; Magidor M., Group radicals and strongly compact cardinals, Trans. Amer. Math. Soc. 366 (2014), no. 4, 1857-1877 [2] Bagaria J.; Magidor M., On \(\omega_1\)-strongly compact cardinals, J. Symb. Log. 79 (2014), no. 1, 266-278 [3] Dugas M.; Göbel R., Every cotorsion-free ring is an endomorphism ring, Proc. London Math. Soc. (3) 45 (1982), no. 2, 319-336 [4] Eklof P. C.; Mekler A. H., Almost Free Modules, Set-theoretic methods, North-Holland Mathematical Library, 65, North-Holland Publishing, Amsterdam, 2002 [5] Göbel R.; Shelah S., \( \aleph_n\)-free modules with trivial duals, Results Math. 54 (2009), no. 1-2, 53-64 [6] Göbel R.; Trlifaj J., Approximations and Endomorphism Algebras of Modules, Volume 1., Approximations, De Gruyter Expositions in Mathematics, 41, Walter de Gruyter GmbH & Co. KG, Berlin, 2012 [7] Herrlich H.; Tachtsis E., On the solvability of systems of linear equations over the ring \(\mathbb Z\) of integers, Comment. Math. Univ. Carolin. 58 (2017), no. 2, 241-260 [8] Kanamori A., The Higher Infinite: Large Cardinals in Set Theory from Their Beginnings, Springer Monographs in Mathematics, Springer, Berlin, 2003 [9] Shelah S., Quite free complicated abelian group, PCF and black boxes, available at ArXiv: 1404.2775v2 [math.LO] (2019), 49 pages This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.