The Faculty of Science and the Leiden Institute of Advanced Computer Science (LIACS) is looking for a:
PhD Candidate on Expressivity of Imperative Programs (1.0 FTE)
The semantics of programming languages are often modeled as abstract machines that evolve through interaction with their environment, raising the question of whether every machine behavior can be captured by a program in a given language. This question has practical implications, such as in compiler optimizations and decompilation for tasks like malware analysis. However, theoretical limits exist: languages lacking non-local control flow constructs like goto or break cannot express all machine behaviors. This issue, rooted in debates dating back to the 1980s, continues to inspire research, especially into the expressiveness of structurally constrained control flows. This PhD project explores these questions through the lenses of programming languages, automata theory, and process algebra.
Key responsibilities
The candidate will be embedded in the Theory cluster at the Leiden Institute of Advanced Computer Science, supervised by Dr. Tobias Kappè and Prof. Dr. Marcello Bonsangue from the System Modelling and Analysis lab. More information can be found at https://www.universiteitleiden.nl/en/science/computer-science/research/theory. The successful candidate will conduct original and novel research at the intersection of programming language semantics, automata theory, and algebraic reasoning, publish and present scientific articles in top theory venues, contribute to educational activities as a (head) teaching assistant and finally write a PhD thesis detailing the outcome of the research activities.
Selection criteria
- A master’s (or equivalent) degree in Computer Science, Mathematics, Logic, or a highly related field;
- Affinity with formal methods, including an understanding of basic of automata theory, formal languages, algorithms, and computability --- i.e., foundational computer science theory. Candidates with a background in mathematics or logic should be able to pick up on these topics relatively quickly;
- Intrinsic motivation to perform foundational computer science research, internalize with cutting-edge theory, and synthesize new results;
- Prior experience with academic writing (existing published work is not strictly necessary, but would help strengthen an application);
- Openness to picking up new skills, such as how to use proof assistants like Rocq, Lean or Isabelle (prior knowledge of these is not required);
- Excellent proficiency in English, both spoken and written (Dutch is not required, but LIACS does subsidize optional Dutch language courses);
- Willingness to participate in educational activities.
- Good research skills;
- Good writing and presentation skills;
- Good teamwork skills.
Research at our faculty
The Faculty of Science is a world-class faculty where staff and students work together in a dynamic international environment. Our people are driven by curiosity to expand fundamental knowledge and to look beyond the borders of their own discipline. The research carried out at the Faculty of Science is diverse, ranging from mathematics, artificial intelligence, computer science, astronomy, physics, chemistry and bio-pharmaceutical sciences to biology and environmental sciences. The faculty has grown strongly in recent years and now has more than 1,300 staff and almost 4,000 students. We are located at the heart of Leiden’s Bio Science Park, one of Europe’s biggest science parks, where university and business life come together. For more information, see https://www.universiteitleiden.nl/en/science.
The Leiden Institute of Advanced Computer Science (LIACS) is the Artificial Intelligence and Computer Science Institute in the Faculty of Science of Leiden University. We offer courses at the Bachelor and Master of Science level in Artificial Intelligence, Computer Science, ICT in Business, Creative Interactions, and Bioinformatics. According to an independent research visitation, we are one of the foremost computer science departments of the Netherlands. We strive for excellence in a caring institute, where excellence, fun, and diversity go hand in hand. We offer a clear and inviting career path to young and talented scientists with the ambition to grow. For more information about LIACS, see https://www.cs.leiden.edu.
Terms and conditions
We offer a full-time position for initially one year. After a positive evaluation of the progress of the thesis, personal capabilities and compatibility, the appointment will be extended by a further three years. Salary ranges from € 2.901, - to € 3.707, - gross per month (pay scale P in accordance with the Collective Labour Agreement for Dutch Universities). All our PhD students are embedded in the Leiden University Graduate School of Science https://www.universiteitleiden.nl/en/science/graduate-school-of-of-science. Our graduate school offers several PhD training courses at three levels: professional courses, skills training and personal effectiveness. In addition, advanced courses to deepen scientific knowledge are offered by the IPA research school (https://ipa.win.tue.nl/). Leiden University offers an attractive benefits package with additional holiday (8%) and end-of-year bonuses (8.3 %), training and career development and sabbatical leave. Our individual choices model gives you some freedom to assemble your own set of terms and conditions. Candidates from outside the Netherlands may be eligible for a substantial tax break.
Diversity and inclusivity
Diversity and inclusion are core values of Leiden University. Leiden University is committed to becoming an inclusive community which enables all students and staff to feel valued and respected and to develop their full potential. Diversity in experiences and perspectives enriches our teaching and strengthens our research. High quality teaching and research are inclusive.
Information
Enquiries can be made to Dr. Tobias Kappè ([email protected]). If you have If you have any questions about the application, please sent an email to: [email protected].
Applications
To apply for this position, please submit your application online via the blue button below the vacancy text at the university website. Please ensure that you attach the following additional documents:
- Curriculum vitae (CV);
- Application letter, including your applicability to aforementioned selection criteria and your preference for the topic;
- MSc (or equivalent) degree (or expected graduation date);
- Full grade list (for both bachelor's degree and master's degree, if applicable);
- Examples of your scientific writing (e.g., (draft of) master’s thesis, scientific publication, course report);
- Contact information of two references (university supervisors or other scientific collaborators) who can be requested by us to send further information;
Only applications received before June 30, 2025, 23:59 CET can be considered. Your application will be treated confidentially and will be assessed by researchers from the Theory Cluster at LIACS, Leiden University.
