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Inductive limits of projective C*-algebras. - IMAR

Inductive limits of projective C*-algebras. - IMAR

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Relations between the different classes I<br />

Lemma 4.1<br />

Given α: A → P, β: P → A with β ◦α = id A and P <strong>projective</strong>.<br />

⇒ A <strong>projective</strong>.<br />

Pro<strong>of</strong>.<br />

Given lifting problem ϕ: A → C/J, need lift ψ : A → C.<br />

A α<br />

P<br />

id A<br />

β<br />

ω<br />

A<br />

C<br />

π<br />

ϕ C/J<br />

P <strong>projective</strong> ⇒ get lift ω: P → C for ϕ◦β: P → C/J<br />

Then ψ := ω ◦α : A → B is desired lift for ϕ<br />

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