منابع مشابه
Reaping Numbers of Boolean Algebras
A subsetA of a Boolean algebra B is said to be (n,m)reaped if there is a partition of unity P ⊂ B of size n such that |{b ∈ P : b∧a 6= ∅}| ≥ m for all a ∈ A. The reaping number rn,m(B) of a Boolean algebra B is the minimum cardinality of a set A ⊂ B\ {0} such which cannot be (n,m)-reaped. It is shown that, for each n ∈ ω, there is a Boolean algebra B such that rn+1,2(B) 6= rn,2(B). Also, {rn,m(...
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The Bruhat order gives a poset structure to any Coxeter group. The ideal of elements in this poset having boolean principal order ideals forms a simplicial poset. This simplicial poset defines the boolean complex for the group. In a Coxeter system of rank n, we show that the boolean complex is homotopy equivalent to a wedge of (n− 1)-dimensional spheres. The number of these spheres is the boole...
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...
متن کاملBoolean Algebras in Visser Algebras
We generalize the double negation construction of Boolean algebras in Heyting algebras, to a double negation construction of the same in Visser algebras (also known as basic algebras). This result allows us to generalize Glivenko’s Theorem from intuitionistic propositional logic and Heyting algebras to Visser’s basic propositional logic and Visser algebras. Mathematics Subject Classification: P...
متن کاملDepth of Boolean Algebras
Suppose D is an ultrafilter on κ and λ = λ. We prove that if Bi is a Boolean algebra for every i < κ and λ bounds the Depth of every Bi, then the Depth of the ultraproduct of the Bi’s mod D is bounded by λ. We also show that for singular cardinals with small cofinality, there is no gap at all. This gives a partial answer to problem No. 12 in [?]. 2000 Mathematics Subject Classification. Primary...
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ژورنال
عنوان ژورنال: Bulletin of the London Mathematical Society
سال: 1996
ISSN: 0024-6093,1469-2120
DOI: 10.1112/blms/28.6.591