Andreas Grigorjew
About me
Welcome! I am a doctoral student at the University of Helsinki in the Department of Computer Science, supervised by Alexandru I. Tomescu. I am part of the Graph Algorithms Team.
My research interests broadly lie in theoretical computer science and include graph theory, algorithms and combinatorics.
In spring 2025, I visited the Applied Algorithms Group at the Montana State University.
In my free time, I enjoy bouldering and spending time in nature. I am also trying to master playing the violin and the Finnish language.
You are welcome to contact me via email: contact [at] andreasgrigorjew [dot] de (PGP key).
Research
Publications and preprints
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Andreas Grigorjew, Wanchote Jiamjitrak, Brendan Mumey, Alexandru I. Tomescu
Parameterised Approximation and Complexity of Minimum Flow Decompositions
arXiv, 2024 (view preprint)
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Andreas Grigorjew, Fernando H. C. Dias, Andrea Cracco, Romeo Rizzi, Alexandru I. Tomescu
Accelerating ILP solvers for Minimum Flow Decompositions through search space and dimensionality reductions
SEA 2024 - International Symposium on Experimental Algorithms, 14:1-14:19, 2024 (view)
Best paper award runner-up
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Manuel Cáceres, Massimo Cairo, Andreas Grigorjew, Shahbaz Khan, Brendan Mumey, Romeo Rizzi, Alexandru I. Tomescu, Lucia Williams
Width Helps and Hinders Splitting Flows
ACM Transactions on Algorithms, 20(2), 1--20, 2024 (view extended version)
ESA 2022 - European Symposium on Algorithms (Track A), 31:1--31:14, 2022 (view)
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Andreas Grigorjew, Artur Gynter, Fernando Dias, Benjamin Buchfink, Hajk-Georg Drost*, Alexandru I. Tomescu*
Sensitive inference of alignment-safe intervals from biodiverse protein sequence clusters using EMERALD
Genome Biology 24, 168, 2023 (view)
*Equal contribution
Software
- Optimized FD: An optimized flow decomposition solver using Integer Linear Programming, for exact optimum and heuristic solutions (GitHub).
Flow decompositions are used e.g. for RNA transcriptict assembly or viral strain reconstruction.
- EMERALD: a protein sequence aligner that finds safety windows, protein regions preserved in the suboptimal alignment space (GitHub).
Teaching
I was a teaching assistant in the following courses holding exercise classes:
- Models of Computation, spring 2024 (Helsinki)
- Models of Computation, spring 2023 (Helsinki)
- Elements of Bioinformatics, autumn 2022 (Helsinki)
- Design and analysis of algorithms, autumn 2021 (Helsinki)
- Mathematik für Data Science und Physik Studierende I, winter 2021 (Erlangen)
- Analysis III, winter 2019 (Erlangen)
- Theorie der Programmierung, summer 2019 (Erlangen)
- Theorie der Programmierung, summer 2018 (Erlangen)
Education
- since April 2021: Doctoral student in the Department of Computer Science at the University of Helsinki
- October 2018 until March 2021: Master of Science in Mathematics at the Friedrich-Alexander-Universität Erlangen-Nürnberg
- January 2020 until May 2020: Exchange semester at the University of Helsinki
- October 2015 until July 2018: Bachelor of Science in Mathematics at the Friedrich-Alexander-Universität Erlangen-Nürnberg