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Alumna Interview: Gresham Professor of Geometry, Sarah Hart

For the second edition of the alumnae newsletter we had the privilege of interviewing Professor Sarah Hart (Class of 1993). She is head of Mathematics and Statistics at Birkbeck and in 2020 became the first woman to be appointed to the UK's oldest chair of mathematics. As Gresham Professor of Geometry, Sarah delivers a free lecture series exploring mathematics, culture, and creativity, which can be viewed online here.

How has your enthusiasm for studying mathematics within its cultural context influenced your work?  

As a mathematician, I have always picked up on mathematics in literature, art, and music. This might be where mathematical concepts are mentioned in favourite novels, or particularly beautiful symmetrical designs in art, where I wonder about the underlying mathematics. I think of mathematics as really the best way we have to understand pattern and structure, which are themselves fundamental to how the universe works. We as humans are part of that universe, so it’s no surprise that we are drawn on a basic level to pattern and structure ourselves, and that we find those things pleasing and satisfying when we encounter them in art, either consciously or subconsciously. The music of Bach, the beauty of geometric design in Islamic art, or the rhythm and structure of a sonnet, all these are mathematics made manifest. Most of my career has been spent studying pure mathematics in and of itself, but my fascination with how mathematics interacts with the arts has meant that over the years I’ve come to be familiar with these interactions, and that meant I was able to put together an interesting programme of public lectures in my application for the role of Gresham Professor of Geometry that ultimately secured me the job. I’ve also written a research article about mathematics in Moby-Dick, the novel by Hermann Melville.  

You have spoken about the gender disparity within mathematics – what more do you think can be done to solve this issue?  

The first thing to emphasise is that it is clear that there is no disparity in terms of actual ability between the genders. The gender imbalance in mathematics shows a “leaky pipeline” effect, where there is almost parity now in undergraduate degree courses (I think 45% women to 55% men), but the number drops at PhD level, then again at each level up to Professor. When I became a Professor in 2013, I checked and only 6% of Maths Professors were women – there were 50 of us in the UK at that point. I think this is now up to 9%, so it’s improving slightly. There is still work to do to make academia in general, and mathematics in particular, much more diverse and inclusive. This is a wider issue than mathematics, of course. Nobody really knows the full explanation. In part it is about the research environment where you need to produce lots of good research just at the moment where many women may be starting families (men too, but they don’t tend to take as much parental leave). Women who make the decision to have children need to have much more support getting back into research after maternity leave or career breaks – you know how you forget everything over the Summer holidays? Imagine that for abstract algebra after a year away! Another possible reason for the leaky pipeline is about a subconscious feeling of not belonging that you can occasionally experience if you are regularly the only woman in the room over several years. But also, things like conferences where all the speakers are white men (usually done completely accidentally), or conferences where there are 19 white men and one woman, who is then assumed to be the token woman and not deserving of her position, should be a thing of the past! 

What advice would you give mathematics graduates on finding careers which will make the most of their skills?  

There’s the old line that if you find a job you love, you never have to do a day’s work again. This is slightly unrealistic, but I am a huge fan of following your passions. You never know where it might lead. My interest in the intersections of mathematics and culture was purely for fun, and did not “pay off” in terms of career progression for 20 years, nor did I pursue that interest with an idea of it affecting my career. So the first thing is always to find time for the things that interest you. Having said that, mathematics graduates really have the world at their feet. Even having a maths A level corresponds to a 10% higher average salary, studies have shown. A mathematics degree gives you so many fantastic skills – not just the obvious quantitative ones of being able to analyse data and solve equations, but more important is the way mathematics teaches you to think. A mathematical proof requires carefully thinking through a question in a logical structured way, covering all the possibilities, testing your hypotheses to make sure your argument really is watertight. This kind of reasoning is an incredibly useful skill that can be applied in all sorts of areas, from finance to coding, from psychology to engineering. Pretty much every industry has mathematical roles. If you like medicine, you could be a mathematician or data scientist in a pharmaceutical company, for instance.  

As a professor and a mother, you fulfil several wide-ranging and demanding roles. How have you found managing all these during the pandemic?  

Difficult! I have always been good at time management, but I’ve had to become exceptional at it! I have one daughter in primary school and one in secondary school. They have been home-learning for six months of the past year, and our usual holiday clubs and other childcare have of course not been available. Thank goodness that my husband and I are a real team – we share our home responsibilities, make sure the children are looked after and happy, and hang the dusting! I get up early to do some work before the kids are awake, as well, which is easier now the days are getting longer again! 

How would you say your experience at CLSG shaped your future career path?  

CLSG has the outlook that everything is possible if you put in the hard work. My mother was actually a maths teacher at CLSG when I was there, and she taught me A-level maths! She and the school encouraged me to pursue my dreams of reading maths at Oxford and then becoming a mathematician. The computer studies teacher let me use the computer room at lunchtime to draw fractals! But also there was a wide range of subjects to study – I’ve always loved languages, and was delighted to have been able to study not just French but Latin and Russian at GCSE, and of course we regularly had theatre trips and other things. You never know when some of this knowledge is going to come in handy later!  

What is your favourite research project that you’re working on right now and why?  

At the moment I’m researching where our words for mathematical symbols come from. My favourite fact at the moment is that our word for sine comes from the Latin word sinus that means a cavity (like the sinuses in our bodies), but this is a translation from the Arabic word jiba for cavity, which itself is a mis-transcription of an ancient Sanskrit word jiva that doesn’t mean cavity at all, it means bowstring, because the diagram representing the sine of an angle from a segment of a circle looks like a drawn bow! 

Your Gresham Lecture Series, Mathematics in Music and Writing, illustrates how mathematics is connected to the creative arts. What do you think are the benefits of recognising this?  

For anyone interested in the creative arts, being aware of some of the mathematics behind them can only enrich your understanding and appreciation. If you are a writer, musician, or artist, knowing about interesting mathematical structures can give you inspiration for new ways to create art – a great example of this is how the artist M. C. Escher learnt about new kinds of tessellations from the mathematician Donald Coxeter, and he used them to create beautiful new designs. Finally, if you are a mathematician, then uncovering the symmetries and patterns of the creative arts can lead to exciting new challenges to solve and avenues to explore.