Symbolic computation lab · Athens & Istanbul

One lab,
two shores of the Aegean.

ALCYON stands for ALgorithms for Combinatorics, geometrY, Optimization and Number theory. We improve the mathematics behind algorithms and turn it into fast, careful software. We do this from two nodes, in Athens and Istanbul.

Our research Join the lab →

Two lattice points, Athens and Istanbul, joined by an arc across a lattice polytope ATHENS 37.97° N · 23.78° E ISTANBUL 40.81° N · 29.36° E

Athens node Αθήνα

National and Kapodistrian University of Athens

The Athens node sits in the Department of Mathematics of the University of Athens. It works on the mathematics behind our algorithms, from polyhedral geometry and generating functions to symbolic linear algebra, and on mathdata, our system for representing mathematical objects.

Members
2
Coordinates
37.97° N · 23.78° E
Visit the Athens node →

Istanbul node İstanbul

Gebze Technical University

The Istanbul node is where ALCYON started, at Gebze Technical University. It works on computer algebra and effective algebraic geometry, including real solving and Hermite methods, hosts most of our funded projects and theses, and ran the Symbolic Computation Istanbul Meetings (SCIM) from 2021 to 2023.

Members
5
Coordinates
40.81° N · 29.36° E
Visit the Istanbul node →

What we work on

Research & software →

Computer Algebra

Algorithmic methods in commutative algebra, including the study of resultant systems.

Effective Algebraic Geometry

Singularities, real solving and the algorithmic tools needed to explore them, such as Hermite matrices and their signatures.

Optimization

Integer linear optimization. We use Polyhedral Omega to solve ILPs, and ILP to improve polynomial multiplication algorithms.

Polyhedral Geometry

Efficient computation with polyhedra, and polyhedral methods that improve algorithms across combinatorics and algorithm design.

Number Theory

Computational questions and algorithmic tools arising from integer partitions.

  • Athens
    Talk at the 96th Séminaire Lotharingien de Combinatoire

    Zafeirakis Zafeirakopoulos gives the talk Generating functions and interpolation at the 96th Séminaire Lotharingien de Combinatoire in Strobl, Austria.

  • Athens
    Eugenia Maria Betsani presents at CASC 2026

    Eugenia Maria Betsani, an undergraduate student in the Athens node, presents joint work with Zafeirakis Zafeirakopoulos at CASC 2026 in Bath, UK: Sparse multivariate interpolation and rational generating functions of polyhedra, on using sparse interpolation to efficiently compute rational generating functions of lattice points in polyhedra.

  • Athens
    Small Resultant Systems via Linear Combinations on arXiv

    Our work with Mahmut Levent Doğan and Elias Tsigaridas, Small Resultant Systems via Linear Combinations, is now on arXiv.

  • Istanbul
    Research visit to Sorbonne Université

    Tülay Ayyıldız visits Sorbonne Université, Paris, in August–September 2026, hosted by Elias Tsigaridas, with a PRESTIJ Research Fellowship from the Embassy of France in Türkiye.

Recent publications

All →
  1. conference

    Sparse multivariate interpolation and rational generating functions of polyhedra

    Eugenia Maria Betsani, Zafeirakis Zafeirakopoulos

    CASC 2026, 28th International Workshop on Computer Algebra in Scientific Computing, Bath, UK, 2026

  2. conference

    Certified Real Eigenvalue Location

    Baran Solmaz, Tülay Ayyıldız

    27th International Symposium on Symbolic and Numeric Algorithms for Scientific Computing (SYNASC 2025), pp. 30–36, 2025

  3. journal

    A Julia Package for Polyhedral Omega and Applications

    Tülay Ayyıldız, Deniz Naz Demirel, İsmail Tapan, Zafeirakis Zafeirakopoulos

    ACM Communications in Computer Algebra 58(2) (ISSAC 2024 software presentation), 2024

  4. journal

    PTOPO: Computing the geometry and the topology of parametric curves

    Christina Katsamaki, Fabrice Rouillier, Elias P. Tsigaridas, Zafeirakis Zafeirakopoulos

    Journal of Symbolic Computation, 2023 · PDF

Come work with us

We have thesis topics for undergraduate, MSc and PhD students in mathematics, computer science and engineering, at either node or across both.

See open topics