Sh:1008

• Shelah, S. (2013). Non-reflection of the bad set for \check I_{\theta}[\lambda] and pcf. Acta Math. Hungar., 141(1-2), 11–35. arXiv: 1206.2048 DOI: 10.1007/s10474-013-0344-6 MR: 3102967
• Abstract:
  We reconsider here the following related pcf questions and make some advances: (Q1) concerning the ideal \check I_\kappa[\lambda] how much reflection do we have for the bad set S^{bd}_{\lambda,\kappa}\subseteq \{\delta<\lambda: cf(\delta)=\kappa\} assuming it is well defined? (Q2) for an ideal J on \kappa how large are S^{bd}_J[\bar f],S^{ch}_J[\bar f] for \bar f=\langle f_\alpha: \alpha < \lambda\rangle which is <_J-increasing and cofinal in (\prod\limits_{i<\kappa}\lambda_i,<_J)? (Q3) are there somewhat free black boxes?
• Version 2015-05-07_12 (23p) published version (25p)

@article{Sh:1008,
 author = {Shelah, Saharon},
 title = {{Non-reflection of the bad set for $\check I_{\theta}[\lambda]$ and pcf}},
 journal = {Acta Math. Hungar.},
 fjournal = {Acta Mathematica Hungarica},
 volume = {141},
 number = {1-2},
 year = {2013},
 pages = {11--35},
 issn = {0236-5294},
 mrnumber = {3102967},
 mrclass = {03E04 (03E05)},
 doi = {10.1007/s10474-013-0344-6},
 note = {\href{https://arxiv.org/abs/1206.2048}{arXiv: 1206.2048}},
 arxiv_number = {1206.2048}
}