منابع مشابه
Semi-Cohen Boolean Algebras
We investigate classes of Boolean algebras related to the notion of forcing that adds Cohen reals. A Cohen algebra is a Boolean algebra that is dense in the completion of a free Boolean algebra. We introduce and study generalizations of Cohen algebras: semi-Cohen algebras, pseudo-Cohen algebras and potentially Cohen algebras. These classes of Boolean algebras are closed under completion.
متن کاملOn Semi-boolean-like Algebras
In a previous paper, we introduced the notion of Boolean-like algebra as a generalisation of Boolean algebras to an arbitrary similarity type. In a nutshell, a double-pointed algebra A with constants 0, 1 is Booolean-like in case for all a ∈ A the congruences θ (a, 0) and θ (a, 1) are compementary factor congruences of A. We also introduced the weaker notion of semi-Boolean-like algebra, showin...
متن کاملMaharam Algebras and Cohen Reals
We show that the product of any two nonatomic Maharam algebras adds a Cohen real. As a corollary of this and a result of Shelah [14] we obtain that the product of any two nonatomic ccc Souslin forcing notions adds a Cohen real.
متن کاملComplete Embeddings of the Cohen Algebra into Three Families of C.c.c., Non-measurable Boolean Algebras
Von Neumann conjectured that the countable chain condition and the weak (ω, ω)-distributive law characterize measurable algebras among Boolean σalgebras [Mau]. Consistent counter-examples have been obtained by Maharam [Mah], Jensen [J], Glówczyński [Gl], and Veličković [V]. However, whether von Neumann’s proposed characterization of measurable algebras fails within ZFC remains an open problem. ...
متن کاملRobbins Algebras vs. Boolean Algebras
In the early 1930s, Huntington proposed several axiom systems for Boolean algebras. Robbins slightly changed one of them and asked if the resulted system is still a basis for variety of Boolean algebras. The solution (afirmative answer) was given in 1996 by McCune with the help of automated theorem prover EQP/OTTER. Some simplified and restucturized versions of this proof are known. In our vers...
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ژورنال
عنوان ژورنال: Annals of Pure and Applied Logic
سال: 1997
ISSN: 0168-0072
DOI: 10.1016/s0168-0072(97)00009-2