Archive For Mathematical Logic ( IF 0.4 ) Pub Date : 2021-05-27 , DOI: 10.1007/s00153-021-00776-5 Radek Honzik , Šárka Stejskalová
We show that the tree property, stationary reflection and the failure of approachability at \(\kappa ^{++}\) are consistent with \(\mathfrak {u}(\kappa )= \kappa ^+ < 2^\kappa \), where \(\kappa \) is a singular strong limit cardinal with the countable or uncountable cofinality. As a by-product, we show that if \(\lambda \) is a regular cardinal, then stationary reflection at \(\lambda ^+\) is indestructible under all \(\lambda \)-cc forcings (out of general interest, we also state a related result for the preservation of club stationary reflection).
中文翻译:
小的$$ \ mathfrak {u}(\ kappa)$$ u(κ)为奇数$$ \ kappa $$κ,紧凑度为$$ \ kappa ^ {++} $$κ+ +
我们显示树的性质,固定反射和\(\ kappa ^ {++} \)处的可接近性失败与\(\ mathfrak {u}(\ kappa)= \ kappa ^ + <2 ^ \ kappa一致\),其中\(\ kappa \)是具有可数或不可数同素性的奇异强极限基数。作为副产品,我们表明如果\(\ lambda \)是常规基数,则在所有\(\ lambda \)- cc强迫下(在一般情况下)在\(\ lambda ^ + \)处的静态反射是不可破坏的。有趣的是,我们还陈述了保持球杆静止反射的相关结果。