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2026.02.21

Hyper-dual numbers and higher-order derivatives

Extending dual numbers with multiple independent infinitesimals gives a clean, recursive route to higher-order automatic differentiation, connecting to the labeled rooted trees of Faà di Bruno's formula.

automatic differentiation algebra
2023.11.22

On rooted trees and differentiation

The chain rule for higher order derivatives boasts a wealth of beautiful mathematical structure touching the theory of special rooted trees, group theory, combinatorics of integer partitions, order theory, and many others.

differentiation algebra
2021.08.09

Dual numbers

There is a generalisation of the complex numbers where i²=0 instead of i²=−1. Functions extended to this dual number system have the curious property that we can read off their derivatives if we evaluate them at the dual number x + i.

automatic differentiation algebra
2020.12.20

Reversible optimisers

Reversible neural architectures have been a popular research area in the last few years, but reversibility is also built into many modern day neural optimisers, perhaps serendipitously.

optimisation
2019.12.29

The invention of randomness

Of all the many inventions, concepts, and innovations that have shaped our society today and that we take for granted, there is one that stands out as being somewhat overlooked: randomness.

probability history