Keçkin, Murat.
(Thesis (M.S.) - Bogazici University. Institute for Graduate Studies in Science and Engineering, 2022., 2022)
In 1959, Kadison and Singer asked whether every pure state of the diagonal subspace D(ℓ2) of B(ℓ2) has a unique pure state extension to B(ℓ2). This problem has remained open until 2013; in 2013 it has been solved by a team ...