analysis / Operator algebras; regularity in the Elliott classification program

The Toms-Winter conjecture: strict comparison implies Jiang-Su stability for simple nuclear C*-algebras

Theorem 1.1: strict comparison implies A≅A⊗ZA\cong A\otimes\mathcal Z for every separable simple nuclear non-elementary AA, unital or not. More generally (Theorem 1.2) every separable nuclear algebra whose Cuntz semigroup is almost unperforated and fully almost divisible is Z\mathcal Z-stable, which answers the implication (iii) to (ii) of the nonsimple Toms-Winter problem (STW Problem LXXV) and the abstract Cuntz-semigroup question (STW Problem XXVI). Separability and nuclearity remain hypotheses; nonnuclear and non-separable algebras are not treated.

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analysisSep 23, 2026Significance 48/100Registry: unreviewed

The Toms-Winter conjecture: strict comparison implies Jiang-Su stability for simple nuclear C*-algebras

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Theorem 1.1: strict comparison implies A≅A⊗ZA\cong A\otimes\mathcal Z for every separable simple nuclear non-elementary AA, unital or not. More generally (Theorem 1.2) every separable nuclear algebra whose Cuntz semigroup is almost unperforated and fully almost divisible is Z\mathcal Z-stable, which answers the implication (iii) to (ii) of the nonsimple Toms-Winter problem (STW Problem LXXV) and the abstract Cuntz-se…

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Theorem 1.1: strict comparison implies A≅A⊗ZA\cong A\otimes\mathcal Z for every separable simple nuclear non-elementary AA, unital or not. More generally (Theorem 1.2) every separable nuclear algebra whose Cuntz semigroup is almost unperforated and fully almost divisible is Z\mathcal Z-stable, which answers the implication (iii) to (ii) of the nonsimple Toms-Winter problem (STW Problem LXXV) and the abstract Cuntz-semigroup question (STW Problem XXVI). Separability and nuclearity remain hypotheses; nonnuclear and non-separable algebras are not treated.

Theorem 1.1: strict comparison implies A≅A⊗ZA\cong A\otimes\mathcal Z for every separable simple nuclear non-elementary AA, unital or not. More generally (Theorem 1.2) every separable nuclear algebra whose Cuntz semigroup is almost unperforated and fully almost divisible is Z\mathcal Z-stable, which answers the implication (iii) to (ii) of the nonsimple Toms-Winter problem (STW Problem LXXV) and the abstract Cuntz-semigroup question (STW Problem XXVI). Separability and nuclearity remain hypotheses; nonnuclear and non-separable algebras are not treated.

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The Toms-Winter conjecture: strict comparison implies Jiang-Su stability for simple nuclear C*-algebras — Mathematical Frontier Network