Final Report Summary - GRAPHALGAPP (Challenges in Graph Algorithms with Applications) The project developed a large set of new algorithmic techniques for approximation and graph algorithms, especially dynamic graph algorithms, leading to new algorithms for many dynamic graph problems such as finding shortest paths or dense clusters in graphs. Furthermore, we showed that no fast dynamic algorithms can exist for a large set of graph problems. Finally, we also evaluated graph algorithms, both static and dynamic algorithms, empirically and developed the fastest implementations for various graph problems, winning the Parameterized Algorithms and Computational Experiments (PACE) Challenge 2019, as well as Best Paper Awards. To disseminate these results, the PI gave 8 invited keynotes at large international conferences.