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$\begingroup$ Can you provide some additional context? Who has made this conjecture? When? Why? $\endgroup$

Timothy Chow
– Timothy Chow

2026-03-02 12:43:56 +00:00
Commented Mar 2 at 12:43
2

$\begingroup$ @TimothyChow this question appeared during one of the Fields Institute thematic semesters around 2012-2013 and was asked by various people at the same time once it was observed that certain concrete Banach algebras emerged as Calkin algebras of Banach spaces. See also arxiv.org/abs/2101.09950 Morally, this says we don't have reasonable limits for the Fredholm theory of Banach space operators. $\endgroup$

Tomasz Kania
– Tomasz Kania

2026-03-02 12:50:13 +00:00
Commented Mar 2 at 12:50

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