Keller–Lübeck–Lynd–Semikina conjectures for fusion systems

Let F\mathcal{F} be a saturated fusion system on a finite pp-group SS of order pep^e, and let α\alpha be a compatible family. Write ss for the sectional rank of SS, and let r>0r>0 be the smallest positive integer such that, when SS is nonabelian, SS has a character of degree prp^r. The quantities k(F,α)\operatorname{\mathbf{k}}(\mathcal{F},\alpha), w(F,α)\operatorname{\mathbf{w}}(\mathcal{F},\alpha), and m(F,α,d)\operatorname{\mathbf{m}}(\mathcal{F},\alpha,d) are defined above; [S,S][S,S] denotes the derived subgroup of SS. Keller–Lübeck–Lynd–Semikina conjectures. The following assertions hold: (1) k(F,α)=m(F,α)\operatorname{\mathbf{k}}(\mathcal{F},\alpha)=\operatorname{\mathbf{m}}(\mathcal{F},\alpha); (2) k(F,α)S\operatorname{\mathbf{k}}(\mathcal{F},\alpha)\leqslant |S|; (3) w(F,α)ps\operatorname{\mathbf{w}}(\mathcal{F},\alpha)\leqslant p^s; (4) for every positive integer dd, m(F,α,d)0\operatorname{\mathbf{m}}(\mathcal{F},\alpha,d)\geqslant 0; (5) if SS is nonabelian, then m(F,α,d)0\operatorname{\mathbf{m}}(\mathcal{F},\alpha,d')\ne 0 for some ded\ne e; (6) if SS is nonabelian, then rr is the smallest positive integer such that m(F,α,dr)0\operatorname{\mathbf{m}}(\mathcal{F},\alpha,d-r)\ne 0; and (7a) k(F,α)/m(F,α,e)\operatorname{\mathbf{k}}(\mathcal{F},\alpha)/\operatorname{\mathbf{m}}(\mathcal{F},\alpha,e) is at most the number of conjugacy classes of [S,S][S,S], while (7b) k(F,α)/w(F,α)\operatorname{\mathbf{k}}(\mathcal{F},\alpha)/\operatorname{\mathbf{w}}(\mathcal{F},\alpha) is at most the number of conjugacy classes of SS. These conjectures generalize weight and ordinary weight conjectures from blocks to compatible families on saturated fusion systems. The paper states that they will be verified for nonconstrained fusion systems on an extraspecial group, while the assertions are presented here as the seven conjectures from the cited source.

Sources & referencesView supporting material

Primary source

Radha Kessar, Markus Linckelmann, Justin Lynd and Jason Semeraro, “Weight conjectures for fusion systems on an extraspecial group”, arXiv:2505.04840 (2025).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.