There exists a universal control sequence of increasing positive integers such that: Every infinite-dimensional separable Banach space X has a biorthogonal system xₙ,xₙ* with ||xₙ|| = 1 and ||xₙ*|| < K for each n such that, for each x ∈ X, where π(n) is a permutation of n which depends on x but is uniformly controlled by , that is, for each m.
@book{bwmeta1.element.bwnjournal-rm-doi-10_4064-dm439-0-1, author = {Paolo Terenzi}, title = {Every separable Banach space has a basis with uniformly controlled permutations}, series = {GDML\_Books}, year = {2006}, zbl = {1121.46014}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-rm-doi-10_4064-dm439-0-1} }
Paolo Terenzi. Every separable Banach space has a basis with uniformly controlled permutations. GDML_Books (2006), http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-rm-doi-10_4064-dm439-0-1/