Absolute F-sigma delta spaces

Abstrakt

We prove that hereditarily Lindelof space which is F-sigma delta in some compactification is absolutely F-sigma delta. In particular, this implies that any separable Banach space is absolutely F-sigma delta when equipped with the weak topology.

Klíčová slova

• Compactification
• Complexity
• Absolute
• F-sigma delta
• Banach space