Everybody loves a good formula!

I find a 'good formula' to be very inspirational for research: understanding where surprising and powerful formulae in mathematics and physics come from —and why they exist —can be a gateway to finding other such formulae, or cast light on a set of ideas that can take you in exciting new directions. In this talk, I'll try to explain one of my favourite formulae, why you should care about it, and why it's something that's been inspiring me for over 10 years.