Projections in Weakly Compactly Generated Banach Spaces and Chang’s Conjecture
نویسنده
چکیده
Classical results on weakly compactly generated (WCG) Banach spaces imply the existence of projectional resolutions of identity (PRI) and the existence of many projections on separable subspaces (SCP). We address the questions if these can be the only projections in a nonseparable WCG space, in the sense that there is a PRI (Pα : ω ≤ α ≤ λ) such that any projection is the sum of an operator in the closure of the linear span of countably many Pα’s (in the strong operator topology) and a separable range operator. Wark’s modification of Shelah’s and Steprāns’ construction provides an unconditional example for λ = ω1. We note that it is impossible for λ > ω2. 2000 Mathematics Subject Classification. Primary 46B26, 03E35.
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