Minimax exclusivity conjecture for power-type losses

Let p,q>0p,q>0 be distinct exponents, and for each r>0r>0 let Lr\mathcal{L}_r be the class of losses whose local behavior near a=θa=\theta is c(θ)θar+o(θar)c(\theta)|\theta-a|^r+o(|\theta-a|^r) with c(θ)>0c(\theta)>0. Consider minimax optimality over a regular parametric model. Minimax exclusivity conjecture. No estimator is simultaneously minimax for a loss in Lp\mathcal{L}_p and a loss in Lq\mathcal{L}_q. Equivalently, the family {Lr:r>0}\{\mathcal{L}_r:r>0\} forms a minimax exclusivity partition of Lpower=r>0Lr\mathscr{L}_{\mathrm{power}}=\bigcup_{r>0}\mathcal{L}_r. The structural classes are disjoint and closed cones under positive scaling, but whether their structural separation forces minimax exclusivity remains unclear.

Sources & referencesView supporting material

Primary source

Stanisław M. S. Halkiewicz, “Exclusivity Classes and Partitions of Loss Functions”, arXiv:2507.12447 (2026).

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.