David Hilbert

 was a German mathematician. (PROSE: The Turing Test)

He invented Hilbert space-filling curves, (AUDIO: Entanglement) and Hilbert spaces. (PROSE: Christmas on a Rational Planet)

Alan Turing once asked the Eighth Doctor's opinion on a problem with Hilbert's theory of groups.

Hilbert believed that all mathematical problems were solvable. Turing disproved this thesis by demonstrating the existence of undecidable problems in his paper Computable Numbers, which was published before World War II. (PROSE: The Turing Test)

Behind the scenes

 * Hilberta's Hostel is an homage to.