algebra / Representation theory of algebras; homological conjectures

The Nakayama conjecture on dominant dimension

Claims Corollary 1.2: for the symmetric pair (A,M)(A,M) of the Tachikawa counterexample and every field extension KK of F2(q,H1,H2)\mathbb F_2(q,H_1,H_2), the finite-dimensional algebra ΓK=End(AK⊕MK)op\Gamma_K=\mathrm{End}(A_K\oplus M_K)^{op} has all injective terms projective but infinite self-injective dimension, has a nonzero simple SS with Exti(S,ΓK)=0\mathrm{Ext}^i(S,\Gamma_K)=0 for all i≥0i\ge0, and has a projective-injective Wakamatsu tilting module that is not tilting. Hence the classical, generalized and strong Nakayama conjectures, the Auslander-Gorenstein conjecture and the Wakamatsu tilting conjecture all fail. Corollary 1.3: ΓK\Gamma_K has infinite little and big finitistic dimension. It does NOT give characteristic-zero examples.

50Significance / 100
1Frontier events
0Verification tasks
0Recorded attempts

Temporal state

Current frontier

No reconciled state yet.

Append-only history

Frontier timeline

algebraSep 23, 2026Significance 50/100Registry: unreviewed

The Nakayama conjecture on dominant dimension

Prior state unknown→disproved

Claims Corollary 1.2: for the symmetric pair (A,M)(A,M) of the Tachikawa counterexample and every field extension KK of F2(q,H1,H2)\mathbb F_2(q,H_1,H_2), the finite-dimensional algebra ΓK=End(AK⊕MK)op\Gamma_K=\mathrm{End}(A_K\oplus M_K)^{op} has all injective terms projective but infinite self-injective dimension, has a nonzero simple SS with Exti(S,ΓK)=0\mathrm{Ext}^i(S,\Gamma_K)=0 for all i≥0i\ge0, and has a projective-injective Wakamatsu tilting…

SourceReplayReproducedFormal proofStatement auditExternal checkExpert reviewPeer review

Research memory

Claims and attempts

Scoped claims

Source authenticated

Claims Corollary 1.2: for the symmetric pair (A,M)(A,M) of the Tachikawa counterexample and every field extension KK of F2(q,H1,H2)\mathbb F_2(q,H_1,H_2), the finite-dimensional algebra ΓK=End(AK⊕MK)op\Gamma_K=\mathrm{End}(A_K\oplus M_K)^{op} has all injective terms projective but infinite self-injective dimension, has a nonzero simple SS with Exti(S,ΓK)=0\mathrm{Ext}^i(S,\Gamma_K)=0 for all i≥0i\ge0, and has a projective-injective Wakamatsu tilting module that is not tilting. Hence the classical, generalized and strong Nakayama conjectures, the Auslander-Gorenstein conjecture and the Wakamatsu tilting conjecture all fail. Corollary 1.3: ΓK\Gamma_K has infinite little and big finitistic dimension. It does NOT give characteristic-zero examples.

Claims Corollary 1.2: for the symmetric pair (A,M)(A,M) of the Tachikawa counterexample and every field extension KK of F2(q,H1,H2)\mathbb F_2(q,H_1,H_2), the finite-dimensional algebra ΓK=End(AK⊕MK)op\Gamma_K=\mathrm{End}(A_K\oplus M_K)^{op} has all injective terms projective but infinite self-injective dimension, has a nonzero simple SS with Exti(S,ΓK)=0\mathrm{Ext}^i(S,\Gamma_K)=0 for all i≥0i\ge0, and has a projective-injective Wakamatsu tilting module that is not tilting. Hence the classical, generalized and strong Nakayama conjectures, the Auslander-Gorenstein conjecture and the Wakamatsu tilting conjecture all fail. Corollary 1.3: ΓK\Gamma_K has infinite little and big finitistic dimension. It does NOT give characteristic-zero examples.

Recorded attempts

Evidence graph

Connected research record