Strict Dirichlet Pólya Inequality for Simply Connected Planar Domains
Pólya's conjecture asserts that Dirichlet eigenvalues of planar domains satisfy λ_j ≥ 4πj/|Ω|. The paper proves the strict version of this inequality for every bounded simply connected planar domain.
Boundary derivative jets of Dirichlet eigenfunctions are turned into a unitary boundary transport, built on the unilateral shift and its rank-one commutator. Dirichlet resonances are linked to unitary eigenphase crossings through the Dirichlet-to-Neumann map and a Cayley transform. An area identity for the trace of a positive radial generator gives the sharp Weyl coefficient. A Ky Fan estimate leaves a strictly positive remainder, and the general case follows by conformal exhaustion.
The strict inequality |Ω|λ_j(Ω) > 4πj holds for all j ≥ 1 on bounded simply connected planar domains. This theorem and the strict Neumann Pólya inequality for simply connected Lipschitz domains were formalized in Lean 4.
