Even-level description of spectrum objects

Remark 4.3.10. When \(C\) is small, the limit description of \(\Sp (C)\) from Remark 4.3.5 identifies \(\Sp ^{(2)}(C)\) with the analogous limit over the subdiagram indexed by the even natural numbers. Since these are cofinal, the result also follows formally from Theorem 21.5.1.