Gisbert F. R. Hasenjaeger was a German mathematical logician. Independently and simultaneously with Leon Henkin in 1949, he developed a new proof of the completeness theorem of Kurt Gödel for predicate logic. He worked as an assistant to Heinrich Scholz at Section IVa of Oberkommando der Wehrmacht Chiffrierabteilung, and was responsible for the security of the Enigma machine.

Heinrich Scholz was a German logician, philosopher, and Protestant theologian. He was a peer of Alan Turing who mentioned Scholz when writing with regard to the reception of "On Computable Numbers, with an Application to the Entscheidungsproblem": "I have had two letters asking for reprints, one from Braithwaite at King's and one from a professor [sic] in Germany... They seemed very much interested in the paper. [...] I was disappointed by its reception here."