A famous quote attributed to Gordan aboutDavid Hilbert's proof ofHilbert's basis theorem, a result which vastly generalized his result on invariants, is "This is not mathematics; this istheology."[2][8] The proof in question was the (non-constructive) existence of a finite basis for invariants. It is not clear if Gordan really said this since the earliest reference to it is 25 years after the events and after his death. Nor is it clear whether the quote was intended as criticism, or praise, or a subtle joke. Gordan himself encouraged Hilbert and used Hilbert's results and methods, and the widespread story that he opposed Hilbert's work on invariant theory is a myth (though he did correctly point out in a referee's report that some of the reasoning in Hilbert's paper was incomplete).[9][10]
He later said "I have convinced myself that even theology has its merits". He also published a simplified version of the proof.[11][12]
^Paul Gordan Die Redaktion derMathematische Annalen, Mathematische Annalen (in German), March 1914, 73 (3): i–ii, doi:10.1007/BF01456698, S2CID 177804295
^abHarm Derksen, Gregor Kemper. (2002), Derkson, Harm; Kemper, Gregor (eds.),Computational Invariant Theory, Invariant theory and algebraic transformation groups, Springer-Verlag, p. 49,ISBN3-540-43476-3,OCLC49493513.