Suita conjecture

In mathematics, the Suita conjecture is a conjecture related to the theory of the Riemann surface, the boundary behavior of conformal maps, the theory of Bergman kernel, and the theory of the L2 extension. The conjecture states the following: Suita (1972): Let R be an Riemann surface, which admits a nontrivial Green function GRG_{R}. Let ω\omega be a local coordinate on a neighborhood Vz0V_{z_{0}} of z0Rz_{0}\in R satisfying w(z0)=0w(z_{0})=0. Let κR\kappa R be the Bergman kernel for holomorphic (1, 0) forms on R. We define BR(z)dw2:=κR(z)Vz0B_{R}(z)|dw|^{2}:=\kappa _{R}(z)|_{V_{z_{0}}}, and BR(z,t)dωdt:=κR(z,t)B_{R}(z,{\overline {t}})d\omega \otimes d{\overline {t}}:=\kappa _{R}(z,{\overline {t}}). Let cβ(z)c_{\beta }(z) be the logarithmic capacity which is locally defined by cβ(z0):=explimξz(GR(z,z0)logω(z))c_{\beta }(z_{0}):=\exp \lim _{\xi \to z}(G_{R}(z,z_{0})-\log |\omega (z)|) on R. Then, the inequality (cβ(z0))2πBR(z0)(c_{\beta }(z_{0}))^{2}\leq \pi B_{R}(z_{0}) holds on the every open Riemann surface R, and also, with equality, then BR0B_{R}\equiv 0 or, R is conformally equivalent to the unit disc less a (possible) closed set of inner capacity zero.

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Primary source

Wikipedia

Progress summary

Refreshed
Solved

The conjecture was proved in full more than a decade ago, including the precise description of when equality occurs.

Suita posed the conjecture in 1972 for open Riemann surfaces admitting a Green function. It asserts the capacity–Bergman-kernel inequality cβ(z0)2πBR(z0)c_{\beta}(z_{0})^{2}\leq\pi B_{R}(z_{0}) and characterizes equality by a disc with at most a closed polar set removed, apart from the case BR0B_{R}\equiv0.

Known results

  • Błocki (2013) proved the inequality for bounded planar domains.
  • Guan and Zhou (2013–2015) proved the inequality for open Riemann surfaces and established the equality characterization through optimal L2L^{2} extension theorems.
  • The result was published in the 2015 Annals of Mathematics paper on optimal L2L^{2} extension.

2018–2022 further proofs

Guan and Zhou gave a 2018 proof of the equality case independent of L2L^{2} extension, and their 2022 work treats the conjecture as solved while placing it in a broader minimal-integral framework. No counterexample, retraction, or unresolved objection was found.

Current status (as of August 2026): The inequality and its equality characterization are settled for the stated class of open Riemann surfaces; no substantive part of the original conjecture remains open.

Sources

Solutions 0

No solutions have been posted yet.