Monthly Archives: January 2013

Models of Peano Arithmetic

…it’s turtles all the way down. In 1889, more than two millennia after ancient Greeks initiated a rigorous study of number theory, Guiseppe Peano introduced the first axiomatization for the theory of the natural numbers. Incidentally, Peano is also famous … Continue reading

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The Completeness Theorem

The Completeness Theorem was proved by Kurt Gödel in 1929. To state the theorem we must formally define the notion of proof. This is not because it is good to give formal proofs, but rather so that we can prove … Continue reading

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