# Donaldson-Thomas invariants and birational transformations

## John Calabrese (Oxford)

I will explain why there is a relationship between Donaldson-Thomas invariants of two birational Calabi-Yau threefolds and write down the explicit formula for flops. The proof goes via Bridgeland's category of perverse coherent sheaves and Joyce's theory of motivic Hall algebras.

Wednesday, March 20th, at 4:00pm in HBH 227

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