The spectrum of partitions of a Boolean algebra
The spectrum of partitions of a Boolean algebra
复制标题
布尔代数的分区谱
DOI:
10.1007/s001530000065
复制
发表时间:
2001
影响因子:
0.3
通讯作者:
J. Monk
中科院分区:
文献类型:
--
作者:
J. Monk
We introduce some notation which will make it easier to state our results. Suppose that κ, ν, µ are infinite cardinals such that ν≤ µ≤ κ. Sets A and B are ν-almost disjoint (ν-ad) if| A∩ B|< ν. A family A of sets is ν-almost disjoint (ν-ad) if any two members of A are ν-ad. Now let F be a family of sets each of size at least ν. We say that A is F-maximal ν-almost disjoint (F, ν-mad) if A⊆ F, it is ν-ad, and it is maximal among subsets of F which are ν-ad. Equivalently, A is F-maximal ν-almost disjoint if A⊆ F, it is ν-ad, and for each X∈ F there is a Y∈ A such that| X∩ Y|≥ ν. Instead of [κ] κ, κ-mad we say κ-mad or κ-maximal almost disjoint. Now we define