3 papers
math.LO2026
Strong Projective Witnesses
Vera Fischer, Julia Millhouse
We show Shelah's original creature forcing from 1984 strongly preserves tight mad families. In particular, answering questions of Fischer and Friedman and Friedman and Zdomskyy, we…
math.LO2025
Cofinitary groups and projective well-orders
Vera Fischer, Lukas Schembecker, David Schrittesser
We introduce the notion of a tight cofinitary group, which captures forcing indestructibility of maximal cofinitary groups for a long list of partial orders, including Cohen, Sacks…
math.LO2025
Partitions of Baire space into compact sets
Vera Fischer, Lukas Schembecker
Under we construct a partition of Baire space into compact sets, which is indestructible by countably supported iteration and product of Sacks forcing of any length, an…