The existence of free ultrafilters on [omega] does not imply the extension of filters on [omega] to ultrafilters
Mathematical logic quarterly, 2013-08, Vol.59 (4-5), p.258
[Peer Reviewed Journal]
ISSN: 0942-5616 ;EISSN: 1521-3870 ;DOI: 10.1002/malq.201100092 ;CODEN: MLQUEF
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