Askey's convexity conjecture

For −1<α≤12-1<\alpha\leq \tfrac12, let JαJ_\alpha denote the Bessel function of the first kind, let jα,2j_{\alpha,2} be its second positive zero, and define β(α)<α+1\beta(\alpha)<\alpha+1 by ∫0jα,2u−β(α)Jα(u) du=0\int_0^{j_{\alpha,2}}u^{-\beta(\alpha)}J_\alpha(u)\,du=0. Askey's convexity conjecture asserts that β\beta is convex as a function of α\alpha on (−1,12](-1,\tfrac12], equivalently that β′′(α)≥0\beta''(\alpha)\geq 0 wherever the second derivative exists. The endpoint formulation considers the continuous extension β(−1)=0\beta(-1)=0 and asks for convexity on [−1,12][-1,\tfrac12].

References

Primary source

arXiv

Additional references

Progress summary

Refreshed
Claimed solved

An unrefereed preprint claims to prove Askey’s convexity conjecture, including its behavior at the endpoint.

The latest report claims a complete resolution of Askey’s convexity conjecture and its endpoint behavior.

September 9, 2026 preprint

A preprint claims to prove β′′(α)>0\beta''(\alpha)>0 for −1<α≤1/2-1<\alpha\le 1/2, including the endpoint derivative, and to construct a strictly convex extension at α=−1\alpha=-1. This would settle the conjecture and its endpoint behavior, but the work is unrefereed.

Current status (as of September 2026): The conjecture is claimed solved, including the endpoint case, but the proof remains unverified.

Sources

Solutions 0

No solutions have been posted yet.