Lydie Mpinganzima arrived in Sweden for the first time in February 2008. She had applied for a PhD student position in mathematics within the Sida-funded research collaboration between the University of Rwanda (UR) and Sweden, **the UR-Sweden programme**. Thus, she came to the Department of Mathematics at Linköping University, which is the coordinator on the Swedish side of the UR-Sweden programme and partner in one of the sub-programmes.

First, Lydie studied for a Master's degree in mathematics and then continued as a PhD student. She achieved a licentiate degree, which is about half way to a PhD degree, and eventually defended her PhD thesis "Iterative Methods for Solving the Cauchy Problem for the Helmholtz Equation" in May 2014. Thus, she became the first woman in Rwanda's history with a PhD degree in mathematics.

Lydie Mpinganzima is nailing her PhD thesis. Photo credit Gunilla Pravitz

## Postdoctoral fellow at the University of Gothenburg

As a result of her successful PhD studies at Linköping University Lydie was accepted as a postdoctoral fellow at the University of Gothenburg. The announcement of this competitive position was international and outside the UR-Sweden collaboration, which meant that she competed completely on her own merits. She stayed at the University of Gothenburg for about a year and did research in the area of numerical analysis of nanophotonics.

## Teacher and researcher in Rwanda

Today Lydie is doing research and teaches at the University of Rwanda. She still works with her thesis subject and tries to find new methods to solve the Cauchy Problem for the Helmholtz Equation. After her public defence, she has published two more articles. She is also a member of a research group that works with mathematical modelling of cardiovascular respiratory system for sportsmen and patients in Rwanda. Furthermore, she is part of a regional research group with members from East Africa.

## PhD studies at Linköping University

Lydie Mpinganzima on the day of her public defence. Photo credit Karin JohanssonThroughout her PhD studies, Lydie took courses and worked on her thesis at Linköping University in parallel with her teaching at the University of Rwanda when she should be in Rwanda. This is the concept for most PhD students in the UR-Sweden programme. According to Lydie, combining teaching in Rwanda with her thesis work in Linköping went well.

Lydie spent most of the time in Sweden, she enjoyed life here and she also learned Swedish. Even though it was tough and long working days at the end of her thesis work, she enjoyed her time as a PhD student.

– To get the opportunity to develop my knowledge as a teacher means a lot to me personally and for my country, says Lydie.

When asked what she misses from Sweden, Lydie answers that she would like to introduce the Swedish concept "fika" in Rwanda, something she learned to appreciate. Lydie also likes the Swedish word "lagom". She also misses the dark winters because she felt more energetic then and could work a lot.

## Collaboration between the University of Rwanda and Sweden

Lydie Mpinganzima was one of the first PhD students at Linköping University, who was trained in the sub-programme in applied mathematics and statistics. The sub-programme is part of the bilateral **UR-Sweden Programme**, a research training partnership programme funded by the Swedish International Development Cooperation Agency (Sida). The aim of the sub-programme is to strengthen research and postgraduate training in mathematics, statistics and their applications at the University of Rwanda.

## Theses at Linköping University

- PhD thesis 2014: Iterative Methods for Solving the Cauchy Problem for the Helmholtz Equation
- Licentiate thesis 2012: An alternating iterative procedure for the Cauchy problem for the Helmholtz equation