Just so I have these somewhere, these are the notes/slides for the two talks I gave at the annual Australian Mathematical Society talk last week. The first is a revision of this talk.

*Localising by spans and cospans, and functoriality of associated algebras*(pdf scan of notes) – see also The elementary construction of formal anafunctors, Cofibrations of internal groupoids and localisations by cospans and Localisation by cospans redux*A descent-theoretic proof of a theorem of Serre*(slides)

https://vixra.org/abs/1909.0638

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I approved this comment, because it is a cute geometric proof of a trig relation. Usually I wouldn’t pass on vixra links, but this seems ok, if not exactly earth-shattering.

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