自由阿贝尔群 (Chinese Wikipedia)

Analysis of information sources in references of the Wikipedia article "自由阿贝尔群" in Chinese language version.

refsWebsite
Global rank Chinese rank
3rd place
8th place
451st place
935th place
2nd place
23rd place
1st place
1st place
69th place
254th place
11th place
332nd place
18th place
57th place
102nd place
492nd place
26th place
113th place

ams.org

arxiv.org

books.google.com

doi.org

handle.net

hdl.handle.net

harvard.edu

ui.adsabs.harvard.edu

jstor.org

  • Blass, Andreas, Injectivity, projectivity, and the axiom of choice, Transactions of the American Mathematical Society, 1979, 255: 31–59, JSTOR 1998165, MR 0542870, doi:10.1090/S0002-9947-1979-0542870-6可免费查阅 . For the connection to free objects, see Corollary 1.2. Example 7.1 provides a model of set theory without choice, and a non-free projective abelian group in this model that is a subgroup of a free abelian group , where is a set of atoms and is a finite integer. Blass writes that this model makes the use of choice essential in proving that every projective group is free; by the same reasoning it also shows that choice is essential in proving that subgroups of free groups are free.

semanticscholar.org

api.semanticscholar.org

web.archive.org