naa a22 4500 510782337 CHVBK 20180411083251.0 cr unu---uuuuu 180411e20131101xx s 000 0 eng 10.1007/s11856-013-0026-7 doi (NATIONALLICENCE)springer-10.1007/s11856-013-0026-7 Stability constants and the homology of quasi-Banach spaces [Elektronische Daten] [Félix Sánchez, Jesús Castillo] We affirmatively solve the main problems posed by Laczkovich and Paulin in Stability constants in linear spaces, Constructive Approximation 34 (2011), 89-106 (do there exist cases in which the second Whitney constant is finite while the approximation constant is infinite?) and by Cabello and Castillo in The long homology sequence for quasi-Banach spaces, with applications, Positivity 8 (2004), 379-394 (do there exist Banach spaces X, Y for which Ext(X, Y) is Hausdorff and nonzero?). In fact, we show that these two problems are the same. Hebrew University Magnes Press, 2013 Sánchez Félix Departamento de Matemáticas, UEx, 06071, Badajoz, Spain aut Castillo Jesús Departamento de Matemáticas, UEx, 06071, Badajoz, Spain aut Israel Journal of Mathematics Springer US; http://www.springer-ny.com 198/1(2013-11-01), 347-370 0021-2172 198:1<347 2013 198 11856 https://doi.org/10.1007/s11856-013-0026-7 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11856-013-0026-7 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sánchez Félix Departamento de Matemáticas, UEx, 06071, Badajoz, Spain aut NATIONALLICENCE 700 1- Castillo Jesús Departamento de Matemáticas, UEx, 06071, Badajoz, Spain aut NATIONALLICENCE 773 0- Israel Journal of Mathematics Springer US; http://www.springer-ny.com 198/1(2013-11-01), 347-370 0021-2172 198:1<347 2013 198 11856 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer