On the groupwise density number for filters
Heike Mildenberger · Czech digital mathematics library · 2005
We consider the groupwise density number g^ for groupwise dense ideals or for non-meagre filters.We answer a question by Taras Banakh on the value g/in the known models of g < mcf and one by Boaz Tsaban on the value of g^ in the Hechler model.As a by-product we prove that g = fr^ in the Hechler model, which was conjectured by Blass, Brendle, Eisworth, Shelah and others.