The Subnormalizer Conjecture

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Let GG be a finite group and let HH be a subgroup. Define the subnormalizer

SG(H)={g∈G∣H⊴⊴⟨H,g⟩}S_G(H)=\{g\in G\mid H\trianglelefteq\trianglelefteq\langle H,g\rangle\}

and the subnormalizer subgroup Sub⁡G(H)=⟨SG(H)⟩\operatorname{Sub}_G(H)=\langle S_G(H)\rangle. For a cyclic subgroup H=⟨x⟩H=\langle x\rangle, write Sub⁡G(x)=Sub⁡G(H)\operatorname{Sub}_G(x)=\operatorname{Sub}_G(H). For a pp-element xx, define Irr⁡x(G)={χ∈Irr⁡(G)∣χ(x)≠0}\operatorname{Irr}^x(G)=\{\chi\in\operatorname{Irr}(G)\mid\chi(x)\neq0\}. The Subnormalizer Conjecture. There exists a bijection

f:Irr⁡x(G)⟶Irr⁡x(Sub⁡G(x))f:\operatorname{Irr}^x(G)\longrightarrow\operatorname{Irr}^x(\operatorname{Sub}_G(x))

such that, for every χ∈Irr⁡x(G)\chi\in\operatorname{Irr}^x(G),

χ(1)p=f(χ)(1)p\chi(1)_p=f(\chi)(1)_p

and

Q(χ(x))=Q(f(χ)(x)).\mathbb{Q}(\chi(x))=\mathbb{Q}(f(\chi)(x)).

The conjecture is motivated by computational evidence, including the symmetric-group example given in the source, and remains open.

References

Primary source

Alexander Moretó, “The Main Problem of Block Theory: Picky Elements and Subnormalizers”, arXiv:2604.24565 (2026).

Additional references

2 papers in this index state this conjecture (2025–2026). The statement above is taken from the most recent of them; the others are arXiv:2508.05180.

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