The reference defintely isn't obvious, at all; it just pleases the referees and participants of the POTY contests.
This is David Hilbert in person, the guy who invented the "quick and dirty" approach to each and every computable problem imaginable.
Layman: "Is it a bug or is it a feature of the ordinary real numbers that you are unable to divide by zero?"
Hilbert: "It is a feature, of course, just define the number 1/0 to be equal to any infinity you are able to imagine."