New proof tightens the de Bruijn–Newman constant to 0.1787854

A new ceiling for Λ: the de Bruijn–Newman constant is at most 0.1787854

Jude Gomila presents a computer-assisted proof that the de Bruijn–Newman constant Λ is at most 0.1787854, improving the previous bound of 0.2. This constant is deeply tied to the Riemann hypothesis: RH holds if and only if Λ ≤ 0. The proof uses the Polymath 15 criterion and interval certificates, with all claims machine-checked and available in an audit repository. The author walks through the entire proof step by step, explaining the heat-flow analogy and the three finite checks that establish the new ceiling.