We prove that the quasi-Banach spaces and (0 < p < 1) have a unique unconditional basis up to permutation. Bourgain, Casazza, Lindenstrauss and Tzafriri have previously proved that the same is true for the respective Banach envelopes and ℓ₁(ℓ₂). They used duality techniques which are not available in the non-locally convex case.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm150-1-4, author = {F. Albiac and C. Ler\'anoz}, title = {Uniqueness of unconditional basis of $l\_{p}(c0)$ and $l\_{p}(l2)$, 0 < p < 1}, journal = {Studia Mathematica}, volume = {151}, year = {2002}, pages = {35-52}, zbl = {1031.46006}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm150-1-4} }
F. Albiac; C. Leránoz. Uniqueness of unconditional basis of $ℓ_{p}(c₀)$ and $ℓ_{p}(ℓ₂)$, 0 < p < 1. Studia Mathematica, Tome 151 (2002) pp. 35-52. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm150-1-4/