From a post of April 1 —
A related post by Terry Tao on September 14, 2007 —
The comments on Tao's post contain a reference to Polya's classic
Induction and Analogy in Mathematics . (See pp. 15-17.) Polya notes
on page 15 —
"Generalization, Specialization, and Analogy often concur
in solving mathematical problems. Let us take as an example
the proof of the best known theorem of elementary geometry,
the theorem of Pythagoras. The proof that we shall discuss is
not new; it is due to Euclid himself (Euclid VI, 31)."
