Guirao Sánchez, Antonio José; Lissitsin, A.; Montesinos Santalucia, Vicente(Elsevier, 2019-11-01)
[EN] A Banach space X has the so-called ball-covering property whenever its unit sphere can be covered by a countable collection of open balls that miss the origin. If 0 < alpha < 1, then X has the alpha-ball covering ...