bradycardia
发表于 2025-3-21 19:16:31
书目名称Cardinal Functions on Boolean Algebras影响因子(影响力)<br> http://impactfactor.cn/if/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras影响因子(影响力)学科排名<br> http://impactfactor.cn/ifr/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras网络公开度<br> http://impactfactor.cn/at/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras网络公开度学科排名<br> http://impactfactor.cn/atr/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras被引频次<br> http://impactfactor.cn/tc/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras被引频次学科排名<br> http://impactfactor.cn/tcr/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras年度引用<br> http://impactfactor.cn/ii/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras年度引用学科排名<br> http://impactfactor.cn/iir/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras读者反馈<br> http://impactfactor.cn/5y/?ISSN=BK0221847<br><br> <br><br>书目名称Cardinal Functions on Boolean Algebras读者反馈学科排名<br> http://impactfactor.cn/5yr/?ISSN=BK0221847<br><br> <br><br>
Munificent
发表于 2025-3-21 22:09:07
http://reply.papertrans.cn/23/2219/221847/221847_2.png
Stricture
发表于 2025-3-22 01:22:36
Cardinality,.. = 2. for A satisfying CSP. W. Just has shown that it is consistent to have a BA . such that ω. ≤ Card.. = |.| < 2ω. Questions about Card. are connected to some problems about cofinality and related cardinal functions which will not be considered here; see van Douwen . The cardinal function Card. is defined as follows:
thalamus
发表于 2025-3-22 05:46:15
Character,. ∈ . and ... = 0 for . ∉ .. Then . is the set of all.such that .. ≤ . for some cofinite subset . of .. So, it is clear that . ≤ .|. If . is a set of generators for . with |.| < |.|, then there is a . ∈ . such that . ⊆ .. for infinitely many cofinite subsets . of .; this is clearly impossible.
neutralize
发表于 2025-3-22 10:20:51
http://reply.papertrans.cn/23/2219/221847/221847_5.png
爱国者
发表于 2025-3-22 15:08:58
http://reply.papertrans.cn/23/2219/221847/221847_6.png
爱国者
发表于 2025-3-22 17:35:17
https://doi.org/10.1007/978-981-99-7879-3of . such that . ⊆ .. But it is a very elementary exercise to show that no ultrafilter is included in a finite union of other, different, ultrafilters. So, t. ≥ ., and hence t. ≥ . for every infinite BA ..
LAP
发表于 2025-3-22 23:15:27
,-Weight, . with π . < π ., and if we take . = . and . = ./Fin, then π . = ω; while π . = 2. since A has a disjoint subset of size 2.. Turning to products, we have (math) for any system (.. : . ∈ .) of infinite BA’s. For, ≥ is clear; now suppose .. is a dense subset of .. for each . ∈ ..
anchor
发表于 2025-3-23 03:51:30
http://reply.papertrans.cn/23/2219/221847/221847_9.png
graphy
发表于 2025-3-23 07:29:28
Tightness,of . such that . ⊆ .. But it is a very elementary exercise to show that no ultrafilter is included in a finite union of other, different, ultrafilters. So, t. ≥ ., and hence t. ≥ . for every infinite BA ..