The main topic of this PhD thesis is the Arakelov ray class group of a number field, an algebraic object that contains both the ideal class group structure and the unit group structure.

This dissertation is a collection of four research articles devoted to the study of Kummer theory for commutative algebraic groups.

The War, Peace and Justice group unites scholars and practitioners to explore war dynamics, peace promotion, and justice’s role in conflict and global affairs.

Our research group Intelligence and Security, provides a diverse range of educational opportunities that combine theoretical foundations with practical applications in intelligence and security.

People are less willing to give up an interest when in a negotiation situation than when they can do it of their own free will, as Leiden University psychologist Eric van Dijk discovered. Knowledge of this kind can be used by policy makers, for instance, to motivate people to adopt certain desirable…

The research group on Diplomacy and Global Affairs studies international diplomacy, international organisation, global, transnational, multi-level and comparative governance.

The Violence and Violence Prevention research group at Leiden University focuses on understanding and preventing violence in modern societies. The group offers two key educational programmes: the Minor Violence Studies and the Governance of Violence specialisation within the Master’s in Crisis and Security…

My work is motivated by the necessity to extend Standard Model of Particle Physics in order to explain three observed phenomena that this great theory fails to accommodate

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The research at The Metabolomics & Analytics Centre is centered around developing innovating analytical methods to enable metabolomics-driven systems biology in personalized health strategies.

This minor focuses on how our thoughts, emotions and behaviour are influenced by other people, and how we influence other people.

I would like to investigate what are the philosophical and practical consequences a reappraisal of the 17th-and 18th-century concept of taste may have for general and historical performance practice.

We are interested in understanding the mechanics of soft materials, of which biological materials are prominent examples.

Promotores: P. Stevenhagen, E. Fouvry (Univeriste Paris Saclay)

Promotor: Prof.dr. P. Stevenhagen & Prof.dr. K. Belabas (Univ. de Bordeaux)

We are cosmologists, in other words we use physics to study the Universe, how it started and evolved into the structure that we observe around us.

The focus of Jan Zaanen's theoretical physics research was the nature of macroscopic matter that is in one or the other way still in the grip of quantum physics.

The Educational Sciences programme group of the Institute of Education and Child Studies at Leiden University provides courses in the field of student education and the learning and development of children in the school context.

Truth is stranger than fiction. In 1997 Juan Maldaceña discovered a remarkable dictionary that translates equation for equation the physics of black holes in string theory into the more conventional physics of quantum mechanics of interacting particles. The remarkable possibility exists that…

The programme group Research Methods and Statistics offers support to researchers from a variety of research projects within Education and Child Studies.

The focus of our theoretical research is understanding the behaviour of soft condensed matter, physical matter which is deformed or structurally altered by thermal fluctuations or small stresses.

Enforcement of group cooperation fails because of discriminatory punishment, according to research by Welmer Molenmaker and colleagues. When group members have different backgrounds, punishment turns into a double-edged sword: no longer used just to prevent group exploitation, but also to break the…

The thesis focuses on synthesis strategies in oligosaccharide campaigns, and the influence of protecting groups.

The development of space resource activities is happening now. In the absence of a clear framework to govern these activities, there is a need to examine the concepts that are being discussed in order to ensure that they meet existing treaty obligations regarding on-orbit operations and space resource…

The Leiden Political Economy Group (L-PEG) is a multi-disciplinary network of scholars with a research interest in (comparative / global) political economy based at Leiden University. Our members belong to various institutes and faculties across Leiden University, and from other universities across…

We explore the particle physics and quantum world at the time of the big bang.

Interest groups play an important role in democratic society.

The group Theoretical Physics of Life Processes, led by Helmut Schiessel, focuses on the physics of chromatin, the DNA-protein complex that fills the nuclei of eukaryotic cells.

The program group Learning and Behavior Problems in Education is located in the Faculty of Social and Behavioural Sciences of Leiden University near Central Station.

The program group Forensic Family and Youth Care Studies is located in the Faculty of Social and Behavioural Sciences of Leiden University near Central Station.

This book offers novel perspectives on the national and international dimensions of the post-war welfare state in Western Europe and North America.

The programme group Parenting, Child Care and Development is located in the Faculty of Social and Behavioural Sciences at Leiden University near Central Station.

‘The storm of the passions rages’: The works of Johannes Jelgerhuis as a source of stagecraft for the historically informed performer.

Industrialised countries extract natural resources in the territories of indigenous peoples, and appropriate the knowledge and culture of these peoples. Leiden anthropologists work to protect the rights of indigenous peoples. Their knowledge and advice enable governments to source sustainable produc…

We study the structure, dynamics and physics of complex networks emerging from the intricate interconnectedness of the constituents of large systems.

The Terrorism and Political Violence research group at Leiden University examines the causes of radicalisation, the tactics of extremist groups, and the effectiveness of counter-terrorism policies. We also explore the role of the media and the influence of postcolonial legacies in the Global South,…

Let A be a commutative algebraic group over a field K, and let G be a finitely generated subgroup of the K-rational points of A. The purpose of this thesis is to study the degrees of the Kummer extensions relative to A,K and G.

Promotor: Prof.dr. W.T.F. den Hollander, Prof. dr. E.A. Verbitskiy

Most of current public-key cryptography is considered insecure against attacks from sufficiently powerful quantum computers. Post-quantum cryptography studies methods to secure information resistant against such attacks. One proposal is isogeny-based cryptography, which bases its security on computational…

Within the bachelor's program of Education and Child Studies, we include the minor Kindermishandeling en Verwaarlozing: een levensloopperspectief and several other courses.

In this thesis we classify the pairs (p,G), where p is a prime number and G is a finite p-group possessing an intense automorphism, i.e. an automorphism that sends each subgroup of G to a G-conjugate, that is non-trivial and whose order is coprime to p.

The aim of this study was to provide insight into how teachers in higher education can be supported in the design, implementation and evaluation of group assignments by developing a theoretical and evidence-based framework for the design of group assignments.

On 1 April 2020, Ivan Romashchenko defended his thesis 'Related Party Transactions and Corporate Groups: When Eastern Europe Meets the West'. The doctoral research was supervised by Prof. S.M. Bartman en Prof. A. Radwan (Kaunas, Lithuania).

Can SMILE, our multi-component intervention, which combines cognitive-behavioural therapy for insomnia, mindfulness, stress, and lifestyle components, improve sleep quality? Can it also improve mood and quality of life and prevent depression and anxiety in the long term?