Tag Archives: Peano arithmetic

Infinity and Foundation

After the reviving effect of a week’s holiday, I have been thinking about Zermelo–Fraenkel set theory, inspired by a very nice student project I supervised (about which I hope to say something here sometime soonish). I have come across a … Continue reading

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On foundations

Jack Edmonds stayed in my house for two and a half weeks, while giving his two courses on polyhedral combinatorics in London (I reported on the second one here). Whenever we spend time together, we have a robust discussion about … Continue reading

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The commutative law

Everybody believes the commutative law for multiplication of natural numbers: for any two natural numbers m and n, we have m × n  =  n × m. But even professional mathematicians have heated debates about exactly what counts as a proof of this law. Here are … Continue reading

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