Today, Alexandra Silva, becomes Professor of Computer Science in the Department of Computer Science in the Ann S. Bowers College of Computing and Information Science. She arrives most recently from the University College London, where she was a Royal Society Wolfson Fellow and Professor of Algebra, Semantics, and Computation.
Commenting on her appointment, Silva writes: “I am very excited to join CS@Cornell! It is a really collegial department, supportive of the younger generation, and with a great atmosphere! I am looking forward to teach, both undergraduate and graduate classes, and to having the opportunity to work with some of the incoming graduate students. I am teaching a large undergraduate introductory class this year (Discrete Structures) and I really look forward to spending time with the students arriving in Ithaca and discovering how special Cornell is!” Thinking of colleagues, she adds: “I am really looking forward to being in the same corridor as Dexter and Nate again! :-) and attending PLDG, where all the PL faculty and grad students gather every week and learn together! The graduate students at Cornell have a very special energy and this is really motivating and inspiring for research!” Silva served as a postdoc with Dexter Kozen, Joseph Newton Pew, Jr. Professor in Engineering and Professor of Computer Science, from March to August 2011, and then visited Cornell again a few times to work with Kozen and Associate Professor Nate Foster.
Asked about her research program, Silva replies: “I work on semantics of programming languages and verification, with a particular focus on the design of methods that are general enough to be applied to different models. A lot of my research uses ideas from a classical area of theoretical computer science, automata theory, seen through the glass of the abstract frameworks of coalgebra and category theory. This perspective has enabled me to derive equivalence and active learning algorithms, as well as proof techniques for completeness, for a large class of automata models. My current projects focus on semantics of probabilistic programming languages and on applying active automata learning in the context of (network) protocol verification.”
Silva, who was recently elected to the 2021 ACM SIGPLAN board as a member-at-large, was given a Suffrage Science Award for “Maths and Computing” in November 2020; a recording of the event is available. For the occasion, she offered the following reflections on her career:
Professor Alexandra Silva is a researcher in algebra, semantics, and computation at University College London (UCL). Having been awarded two prestigious ERC grants, Silva has grown and sustained a large group at UCL that investigates topics related to programming language semantics (the meaning of the languages) and verification. “Coming from the theoretical side it's all at the meta-level in many ways,” Silva said. “We imagine that we have a language and if the language has a number of features, then you can apply methods x, y and z from a generic toolbox. You can use this approach to improve a programming language, to extend the capabilities of a programming language, and use some of the methods to verify that the program does what it's supposed to do.”
Silva has held a passion for mathematics since childhood, but thought she would follow a slightly different path in life. “In high school, I always thought I was either going to be teaching math in schools or be a mathematician analysing models in industry. My parents and my brother kind of convinced me this was not a great idea because employment for mathematicians was not very good in Portugal, where I was studying at that time. I ended up doing this double bachelor's in math and computer science in an attempt to keep my employability higher. In that process I discovered I loved computer science, and even enjoyed it more than the math program.”
“When it came to finding a job at the end of the Bachelors I considered going into industry, but one of my colleagues had just started a PhD in Amsterdam and invited me to visit for a few days. In the end, I decided why not, let's do a PhD. So completely by chance I started a PhD in Theoretical Computer Science, which is like the mathematics of Computer Science in some ways.”
Following her successful PhD, Silva went on to complete a postdoc at Cornell University, looking more at the practical aspects of her theoretical work in programming language semantics. “Whilst I was a graduate student, and also when I was a postdoc, most of the role models and mentors I had were men - and that was fine, I never felt there was a real issue with it. When I became faculty, I suddenly felt the impact of being a woman in a male dominated area. Things changed radically and that was a really tough moment. At that point, I think maybe unconsciously, or maybe later consciously, I started looking around for other women who had made it, to hear about how they had navigated through this.”
Part of the radical change felt by Silva was the greater prevalence of microaggressions. “As you become more senior, these microaggressions actually increase: daily moments where you are made to feel like you're out of place and don't belong because you made a remark or a suggestion that a man wouldn't come up with. Or even worse - you mention an idea at the beginning of the meeting, you're not heard, and then at the end of the meeting, someone else mentions it and suddenly the idea is brilliant. When these events happen once, you sort of ignore them, when they happen twice you might still ignore them, and then they pile up and it comes to a point where you start reacting. I have worked really hard, even with a career coach, to learn how to stay above all of this, but it ultimately ends up impacting your happiness. I think, unless we normalize talking about these things, the other side will never understand what women might be feeling.”
Despite these challenges, Silva has forged an impressive career in academia and is currently a Royal Society Wolfson Fellow at UCL. “One of my main lines of work at the moment is developing methods for verifying that software does what it's supposed to be doing. Someone somewhere in the world could replace one line of code and make the software work in a completely different way to what you expect. Having ways of automatically detecting this and raising flags is something that I think the need for will increase more and more. My work is a little piece in a massive puzzle of a whole research community moving towards having high assurances for systems and how systems work.”
Above all, Silva believes in the importance of being excited by her work, and encourages this outlook in her group. “I always say to my students, happy science is better science. Life is too short for sad science. I find it counterproductive to force someone to work on a milestone that they have no interest in working on, because the frustration will just be too much in the long run. Of course, sometimes we have to do things that we don't want to do, but overall, the nice thing about being an academic is that you can guide the sort of things you do. That is why I came and why I have stayed in academia, and I really want my team to feel that way. I always give them a little freedom and so far, it has worked well; they find their way, they come back with excitement about something and that gives me energy. It’s like a feedback loop of energy and excitement!”
Alongside her research, Silva is incredibly passionate about bettering the workplace culture for minority groups, fuelled by her own experiences. “What I don't think we speak openly about is that once we bring more women into a team, how do we change the way that that company has behaved for decades before, to actually now fit this new demographic. All those daily things that might be trivial, like the way they take lunch breaks and their team structure, they need to change because that’s where microaggressions really appear. What we're doing at the moment is hoping that the women will adapt and just deal with it. I think that's a mistake. We shouldn’t be asking the minorities to do all of the work to change this, we should bring in allies.”
“I have actually co-run an Ally Skills workshop at one of the world’s largest logic conferences (FLOC 2018) and at a large programming language conference (POPL). In the three-hour workshop we looked at what the definition of an ally is and what you can do to be an ally and we run through a lot of practical scenarios. People have really appreciated learning about the concept and being given examples of actionable things they can do and say in their daily lives, like calling out people for making bad jokes. Since I took the ‘train the trainers’ workshop and then started running it, I've become much quicker at reacting when I see things that are not acceptable when it comes to the treatment of minorities. I think that allyship is the way to go forward and to really change structural problems.”
As well as having an impact at a structural level, allyship has had a particularly personal impact on Silva as well. “I am one of the lucky ones who has been blessed with a lot of mentors, allies, and role models in the circles I work in. I hope that other people will experience this as well with different sets of people, and hopefully I will serve as an ally and inspiration to someone too. I've always thought that if I inspire one student it has all been worth it. I think that's my biggest career goal; to have one person think that because they met me they decided to forge a certain path.”
Visit Professor Silva’s website for more on her research.