A classification of definable forcings on ω1
Tom 153 / 1997
Fundamenta Mathematicae 153 (1997), 141-144
DOI: 10.4064/fm-153-2-141-144
Streszczenie
Under the assumption of the existence of sharps for reals all simply definable posets on $ω_1$ are classified up to forcing equivalence.
