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 bounded above by 0.1787854, improving the previous limit of 0.2, and the result is unconditional with no unproved conjectures. The bound is expressed exactly as the rational 129/800 + 87677/5 000 000, derived from 3,149,013 + 883 + 1 machine-checked interval certificates. Since 2018 it is known that Λ ≥ 0, so the constant now lies in the interval [0, 0.1787854].