algebra / Representation theory of finite-dimensional algebras; homological algebra

The finitistic dimension conjecture for finite-dimensional algebras

Theorem 1.1: there is a finite-dimensional complex algebra AA with, for each m≥1m\ge1, a finite-dimensional left module NmN_m with 2m−2≤pd Nm<∞2m-2\le\mathrm{pd}\,N_m<\infty; so findim A=∞\mathrm{findim}\,A=\infty and the big finitistic dimension is infinite too, refuting the conjecture for Artin algebras. By Rickard's theorem injective left AA-modules do not generate the derived category. Corollary (left-right asymmetry): an algebra Λ\Lambda with both finitistic dimensions infinite on the left and zero on the right. The construction passes through a finitely presented group algebra with Abels-type central involutions. A companion OpenAI manuscript (Tachikawa family) independently gives characteristic-two examples.

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algebraSep 23, 2026Significance 50/100Registry: lean checked

The finitistic dimension conjecture for finite-dimensional algebras

Prior state unknown→disproved

Theorem 1.1: there is a finite-dimensional complex algebra AA with, for each m≥1m\ge1, a finite-dimensional left module NmN_m with 2m−2≤pd Nm<∞2m-2\le\mathrm{pd}\,N_m<\infty; so findim A=∞\mathrm{findim}\,A=\infty and the big finitistic dimension is infinite too, refuting the conjecture for Artin algebras. By Rickard's theorem injective left AA-modules do not generate the derived category. Corollary (left-right asymmetry): an algebr…

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Theorem 1.1: there is a finite-dimensional complex algebra AA with, for each m≥1m\ge1, a finite-dimensional left module NmN_m with 2m−2≤pd Nm<∞2m-2\le\mathrm{pd}\,N_m<\infty; so findim A=∞\mathrm{findim}\,A=\infty and the big finitistic dimension is infinite too, refuting the conjecture for Artin algebras. By Rickard's theorem injective left AA-modules do not generate the derived category. Corollary (left-right asymmetry): an algebra Λ\Lambda with both finitistic dimensions infinite on the left and zero on the right. The construction passes through a finitely presented group algebra with Abels-type central involutions. A companion OpenAI manuscript (Tachikawa family) independently gives characteristic-two examples.

Theorem 1.1: there is a finite-dimensional complex algebra AA with, for each m≥1m\ge1, a finite-dimensional left module NmN_m with 2m−2≤pd Nm<∞2m-2\le\mathrm{pd}\,N_m<\infty; so findim A=∞\mathrm{findim}\,A=\infty and the big finitistic dimension is infinite too, refuting the conjecture for Artin algebras. By Rickard's theorem injective left AA-modules do not generate the derived category. Corollary (left-right asymmetry): an algebra Λ\Lambda with both finitistic dimensions infinite on the left and zero on the right. The construction passes through a finitely presented group algebra with Abels-type central involutions. A companion OpenAI manuscript (Tachikawa family) independently gives characteristic-two examples.

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The finitistic dimension conjecture for finite-dimensional algebras — Mathematical Frontier Network