Title of article :
Splitting families and forcing
Author/Authors :
Kurili?، نويسنده , , Milo? S.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Abstract :
According to [M.S. Kurilić, Cohen-stable families of subsets of the integers, J. Symbolic Logic 66 (1) (2001) 257–270], adding a Cohen real destroys a splitting family S on ω if and only if S is isomorphic to a splitting family on the set of rationals, Q , whose elements have nowhere dense boundaries. Consequently, | S | < cov ( M ) implies the Cohen-indestructibility of S . Using the methods developed in [J. Brendle, S. Yatabe, Forcing indestructibility of MAD families, Ann. Pure Appl. Logic 132 (2–3) (2005) 271–312] the stability of splitting families in several forcing extensions is characterized in a similar way (roughly speaking, destructible families have members with ‘small generalized boundaries’ in the space of the reals). Also, it is proved that a splitting family is preserved by the Sacks (respectively: Miller, Laver) forcing if and only if it is preserved by some forcing which adds a new (respectively: an unbounded, a dominating) real. The corresponding hierarchy of splitting families is investigated.
Keywords :
Splitting families , forcing , Random forcing , Sacks forcing , Miller forcing , Laver forcing , Hechler forcing , Cohen forcing
Journal title :
Annals of Pure and Applied Logic
Journal title :
Annals of Pure and Applied Logic