| Wednesday 4 June 2025 | |
| Events for day: Wednesday 18 October 2023 |
| 14:00 - 15:00 Combinatorics and Computing Weekly Seminar A Sample of Robert Tarjan's Algorithmic Results School MATHEMATICS Some of the most efficient data structures and graph algorithms are due to Robert Tarjan and his co-authors. We will try to mention a sample of these results. To manage this sample better, we classify it into 4 related groups, and try to make connections within each group, and also connections between groups: 1. Adjacency lists, DFS and strong components, 2-satisfiability, planarity testing, 3-connected components 2. Vertex elimination, chordal graphs, partition refinement 3. Union-find, nearest common ancestor, dynamic trees 4. Amortized list update, Fibonacci heaps, splay trees We may also look at selected resu ... 17:30 - 19:00 Algebraic Geometry Biweekly Webinar Algebraic Varieties in Quantum Chemistry School MATHEMATICS We discuss the algebraic geometry behind coupled cluster (CC) theory of quantum many-body systems. The high-dimensional eigenvalue problems that encode the electronic Schroedinger equation are approximated by a hierarchy of polynomial systems at various levels of truncation. The exponential parametrization of the eigenstates gives rise to truncation varieties. These generalize Grassmannians in their Pluecker embedding. We explain how to derive Hamiltonians, we offer a detailed study of truncation varieties and their CC degrees, and we present the state of the art in solving the CC equations. This is joint work with Fabian Faulstich an ... |