The main result is as follows. Let X be a Banach space and let Y be a closed subspace of X. Assume that the pair has the λ-bounded approximation property. Then there exists a net of finite-rank operators on X such that and for all α, and and converge pointwise to the identity operators on X and X*, respectively. This means that the pair (X,Y) has the λ-bounded duality approximation property.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm217-1-5, author = {Eve Oja and Silja Treialt}, title = {Some duality results on bounded approximation properties of pairs}, journal = {Studia Mathematica}, volume = {215}, year = {2013}, pages = {79-94}, zbl = {1293.46012}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm217-1-5} }
Eve Oja; Silja Treialt. Some duality results on bounded approximation properties of pairs. Studia Mathematica, Tome 215 (2013) pp. 79-94. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm217-1-5/