‘Quite brilliant’ – Cakes, Custard and Category Theory by Eugenia Cheng

ccctIn computer studies, the Stock Control system has a special place in classrooms and textbooks. Whatever aspect of computing is being taught – whether software or hardware, something basic or high-end, there is a time-honoured tradition of illustrating the same using this universally understood example.

In Cakes, Custard and Category Theory, Eugenia Cheng, a Senior Lecturer in Pure Mathematics at the University of Sheffield, has done something similar but gone one step beyond. Using the common-denominator of the kitchen – of cooking – she has attempted to concoct ‘…easy recipes for understanding complex maths.’ But more important than finding of her own ‘Stock Control system’, she has done something a bit special – she has made maths approachable; interesting, even.

The first thing to say about Cakes, Custard and Category Theory is that it is not a ‘maths book’. It’s not some inert text with ten questions at the end of each chapter, custom-made to make you feel stupid when you come unstuck at Q3; Q4 at best. The author’s target audience is not the professional mathematician, or even the maths fanboy (or girl). Rather, she has chosen for herself a tough mission – to put maths on the coffee table. To persuade the person scarred by the subject at school, to look at it afresh. And she succeeds with flying colours. To make Category Theory so light and digestible, is no trivial party trick – serious thought has gone into this. And every strategy that Cheng and her publishers have deployed, has succeeded:

The eye-catching title suggests the pages are filled with ‘fun’ and ‘charming’ recipes, which would both be true and false. There is a danger that the ‘cake’ analogy could corrupt and thus break down for the reader – it could easily be seen as ‘over-reaching’, as something trivial or frivolous, or worse still, patronising. Moreover, if that’s all the book had to offer – this one cake-based party trick – it would soon wear off and become dull. But the author’s genius is in interweaving cakes and custard, and stories from her own schooldays and beyond, with snippets of *conversation* about some mathematical idea. The author is not so much ‘lecturing’, as she is conversing about and around the subject. It’s not so much a maths book – more a book about maths, by proxy.

And those ‘snippets’ – the maths bits – aren’t elaborate, lengthy or dense. They are a mere dip into a conversation that dovetails with something embedded in the real world. As the author writes, ‘…maths is about moving from the real to the abstract and back again,’ and she reinforces this idea in a thousand friendly ways.

Cheng’s own personality really shines through. By conversing with her audience as equals, readers will likely connect with her, which in turn brings down the barriers to the subject.

The title, the book’s physical dimensions (more like a regular book than an academic textbook), the number of pages (under 300) and the font – even the photo of Cheng herself on the front cover – they all serve to make the book approachable.

Category Theory is a branch of maths that stymies even professional mathematicians, and yet by grounding her discussion in the everyday, Cheng’s book never gets ‘scary’. For readers who have even a pinch of native interest, she has masterfully lowered the mental barriers to new vistas. The book makes almost no mathematical demands of the reader, and yet explains ideas around maths, throughout. It is so seamless and so painless, it is quite brilliant.

Any Cop?: Personally, I will hold onto this book and give it to my four year-old, when she is in her teens. What a wonderful work this is.

Tamim Sadikali


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