Playing this video requires the latest flash player from Adobe.

Download link (right click and 'save-as') for playing in VLC or other compatible player.

Recording Details

PIRSA Number: 


Equality of two mathematical objects is a seemingly simple and well-understood concept. In this talk, I will do three things to explain why this is a misconception: I will survey different notions of equality, explain how revising the notion of equality has led to an emerging alternative foundation of mathematics called "homotopy type theory", and try to convince you that thinking about equality is relevant to your research in quantum field theory, quantum gravity or quantum foundations.