We study the notions of acs, luacs and uacs Banach spaces which were introduced by Kadets et al. and form common generalisations of the usual rotundity and smoothness properties of Banach spaces. In particular, we are interested in (mainly infinite) absolute sums of such spaces. We also introduce some new classes of spaces that lie inbetween those of acs and uacs spaces and study their behaviour under the formation of absolute sums as well.
Jan-David Hardtke. "Absolute sums of Banach spaces and some geometric properties related to rotundity and smoothness." Banach J. Math. Anal. 8 (1) 295 - 334, 2014. https://doi.org/10.15352/bjma/1381782101