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Bilde av Riener, Cordian
Bilde av Riener, Cordian
Institutt for matematikk og statistikk cordian.riener@uit.no +4777644090 Tromsø

Cordian Riener

Job description

Mitt vitenskapelige arbeid ligger i samspillet mellom matematikk og teoretisk informatikk. Et fokus i min forskning er på spørsmål knyttet til beregningsmessig kompleksitet av algoritmiske spørsmål i ekte algebraisk geometri og optimalisering. Konkret er jeg interessert i polynomoptimalisering, representasjon av positive polynomer ved summen av kvadrater, momentproblemer, kvadraturformler, algoritmisk kompleksitet, konvekse sett og semibestemt relaksasjon.


Se også min hjemmeside for mer informasjon om forskning og forhåndstrykk.

Jeg leder Algebra-gruppen og er også en av initiativtakerne til Lie-Størmer senter for grunnleggende strukturer i beregnings- og ren matematikk. Jeg fungerer for tiden også som prodekan ved fakultetet for naturvitenskap og teknologi med fokus på PhD-programmet

 

 

  • Jose, Grigoriy, Sebastian, Cordian :
    The Wonderful Geometry of the Vandermonde map
    Foundations of Computational Mathematics 22. septembre 2025 DOI
  • Sebastian, Cordian, Robin Leonid :
    Slices of Stable Polynomials and Connections to the Grace-Walsh-Szegő Theorem
    Journal of symbolic computation 2025 DOI
  • Philippe, Cordian, Robin Leonid :
    Constructively describing orbit spaces of finite groups by few inequalities
    Journal of symbolic computation 2025 DOI
  • Cordian, Jan, Frank :
    A semidefinite programming hierarchy for covering problems in discrete geometry
    Numerical Algebra, Control and Optimization 2025 DOI
  • Ragni, Cordian, Boris :
    Return of the evolute
    Annales de l'Institut Fourier 2025 DOI / ARKIV / FULLTEKST
  • Jose, Grigoriy, Sebastian, Cordian :
    Symmetric nonnegative functions, the tropical Vandermonde cell and superdominance of power sums
    Collectanea Mathematica 2025 DOI
  • Mario, Cordian Benedikt :
    Equivariant algebraic and semi-algebraic geometry of infinite affine space
    Journal of Algebra 2024 DOI / ARKIV
  • Sebastian, Charu, Salma, Cordian Benedikt :
    On nonnegative invariant quartics in type A
    Journal of symbolic computation 2024 DOI / ARKIV
  • Cordian Benedikt, Robin Leonid, Thi Xuan :
    Connectivity in Symmetric Semi-Algebraic Sets
    Association for Computing Machinery 2024 DOI
  • Philippe, Cordian Benedikt, Thorsten, Hugues :
    Symmetric SAGE and SONC forms, exactness and quantitative gaps
    Journal of symbolic computation 2024 DOI
  • Evelyne, Tobias, Philippe, Cordian Benedikt :
    Optimization of trigonometric polynomials with crystallographic symmetry and spectral bounds for set avoiding graphs
    Mathematical programming 2024 DOI / ARKIV
  • Evelyne, Tobias, Cordian Benedikt :
    Orbit Spaces of Weyl Groups Acting on Compact Tori: A Unified and Explicit Polynomial Description
    SIAM Journal on applied algebra and geometry 2024 DOI / ARKIV
  • Philippe, Cordian Benedikt, Hugues :
    Symmetries in Polynomial Optimization
    2023 DOI / ARKIV
  • Gabriella, Cordian, Sarah :
    Attitudes towards mathematics, achievement, and drop-out intentions among STEM and Non-STEM students in Norway
    International Journal of Educational Research Open 2023 DOI / ARKIV
  • Cordian Benedikt, Robin Leonid :
    Linear slices of hyperbolic polynomials and positivity of symmetric polynomial functions
    Journal of Pure and Applied Algebra 2023 DOI / ARKIV
  • Sebastian, Philippe, Cordian Benedikt, Hugues :
    The poset of Specht ideals for hyperoctahedral groups
    Algebraic combinatorics 2023 DOI / ARKIV
  • Thi Xuan, Mohab Safey el, George, Cordian Benedikt, Éric :
    Faster real root decision algorithm for symmetric polynomials
    Association for Computing Machinery 2023 DOI
  • Sebastian, Cordian :
    Reflection groups and cones of sums of squares
    Journal of symbolic computation 2023 DOI / ARKIV
  • Philippe, Helen, Cordian, Thorsten, Hugues :
    Symmetry Reduction in AM/GM-Based Optimization
    SIAM Journal on Optimization 2022 DOI / ARKIV
  • Saugata, Cordian :
    Vandermonde Varieties, Mirrored Spaces, and the Cohomology of Symmetric Semi-algebraic Sets
    Foundations of Computational Mathematics 2021 DOI
  • Philippe, Cordian, Hugues :
    Symmetric ideals, Specht polynomials and solutions to symmetric systems of equations
    Journal of symbolic computation 2021 DOI / ARKIV
  • Grigoriy, Cordian :
    Symmetric Non-Negative Forms and Sums of Squares
    Discrete & Computational Geometry 2020 DOI / ARKIV / FULLTEKST
  • Grigoriy, Mario, Cordian, Markus, Cynthia :
    Generalized eigenvalue methods for Gaussian quadrature rules
    Annales Henri Lebesgue (AHL) 2020 DOI / ARKIV
  • Tobias, Cordian, Raman :
    Reflection groups, arrangements, and invariant real varieties
    Proceedings of the American Mathematical Society 2018 DOI / ARKIV
  • Saugata, Cordian :
    On the equivariant Betti numbers of symmetric definable sets: vanishing, bounds and algorithms
    Selecta Mathematica, New Series 2018 DOI / ARKIV
  • Saugata, Cordian :
    On the Isotypic Decomposition of Cohomology Modules of Symmetric Semi-algebraic Sets: Polynomial Bounds on Multiplicities
    International Mathematics Research Notices (IMRN) 2018 DOI / ARKIV
  • Cordian, Markus :
    Optimization approaches to quadrature: new characterizations of Gaussian quadrature on the line and quadrature with few nodes on plane algebraic curves, on the plane and in higher dimensions
    Journal of Complexity 2018 DOI
  • Saugata, Cordian :
    Bounding the equivariant Betti numbers of symmetric semi-algebraic sets
    Advances in Mathematics 2017 DOI
  • Michal, Bernard, Cordian Benedikt :
    Polynomial Optimization, Moments, and Applications
    Springer 2023 DOI
  • Cordian, Hans Zanna :
    Tiden er inne for Matematikkens hus
    2025
  • Helge, Hans Zanna, Dag Rune, Cordian Benedikt :
    Norge trenger et løft for matematikk på høyt nivå
    Nordnorsk debatt - Nordlys 16. janvier 2025
  • Cordian, Hans, Marta, Elisabeth :
    Women in Mathematics
    2025
  • Cordian :
    The wonderful geometry of the Vandermonde map: Symmetry at infinity and applications
    2025
  • Petter, Elisabeth, Cordian Benedikt :
    Feirer Kvinner i matematikk-dagen på Verdensteatret
    uit.no 2024
  • Gabriella, Cordian Benedikt :
    Disse resultatene i matte og naturfag er et varsko for norsk skole
    Aftenposten 05. décembre 2024 FULLTEKST
  • Gabriella, Sarah Elisabeth, Johanne Sofie, Cordian Benedikt :
    Norwegian students' views on mathematics and mathematicians
    2024
  • Gunnar, Cordian, Satoshi, Kohji :
    MFO-RIMS Tandem Workshop: Symmetries on Polynomial Ideals and Varieties
    Mathematisches Forschungsinstitut Oberwolfach 2022
  • Hugues, Philippe, Cordian, Helen, Thorsten :
    Symmetries in AM/GM-based optimization
    2021
  • Cordian, Ragni :
    Ragni Piene
    2020
  • Cordian, Saugata, Marie Françoise :
    Foreword to the Special Issue dedicated to the Arctic Applied Algebra conference 2019 in Tromsø
    Journal of Pure and Applied Algebra 2020 DOI
  • Cordian :
    Symmetries in algorithmic questions in real algebraic geometry
    2020
  • Cordian :
    Efficiently computing Betti numbers of symmetric semi algebraic sets
    2020
  • Cordian :
    Stand på forskningstorg (Matematiske spill og gåter) under Utforsk UiT, Forskningsdagene 2019
    2019
  • Cordian :
    Algorithms to compute topological invariants of symmetric semi algebraic sets
    2019
  • Cordian :
    Geometry of quadrature rules
    2019
  • Cordian :
    Vandermonde varieties, mirror spaces, and the cohomology of symmetric semi-algebraic sets
    2019
  • Cordian :
    Computing the homology of symmetric semi-algebraic sets
    2018
  • Cordian :
    Efficiently computing the Betti numbers of symmetric semi-algebraic sets
    2018
  • Cordian :
    Semidefinite optimization and arithmetic progressions
    2018
  • Cordian, Mohab Safey el :
    Real Root Finding for Equivariant Semi-algebraic Systems
    2018 ARKIV / FULLTEKST

    • The 50 latest publications is shown on this page. See all publications in Cristin here →

    Research interests

    Real Algebraic Geometry, Optimization, Computational Algebra, Computational Complexity Theory

    Researcher profile in Cristin
    ResearchGate
    ORCID: https://orcid.org/0000-0002-1192-3500

    Member of research group

    Applied and Computational Algebra   English content LIE-STØRMER CENTER   English content MASCOT   English content

    Member of project

    Albatros    English content SymRAG    English content SymRAG POEMA RAGOpt

    CV

    • Siden 2019: Professor i Matematikk, UiT, Tromsø.
    • 2018 - 2019: Førsteamanuensis, UiT, Tromsø.
    • 2016 - 2018: fungerende professor (W2), University Const
    • 2012 - 2016: Aalto Science Institute Fellow, Aalto Ylliopisto, Helsingfors.
    • 2011 - 2012: Associate Fellow, Zukunftskolleg, Konstanz.
    • 2007 - 2011: Stipendiat, Goethe Universität Frankfurt.

     

    Utdanning

    2000 - 2006 Matematisk økonomi (Universität Ulm)
    2003 - 2007 Filosofi (Universität Ulm)
    2004 - 2005 Master 2 i rene matematikk (Université de Bordeaux 1)
    2007 - 2011 Dr. Phil nat i matematikk (Goethe Universität Frankfurt)
    2009 - 2014 Magister Artium i filosofi (Goethe Universität Frankfurt)
    2018 Habilitering i matematikk (Universität Konstanz)
    Stilling

    Siden 2019: Professor, UiT, Tromsø.
    2018 - 2019 Førsteamanuensis, UiT, Tromsø.
    2016 - 2018: Vikarierende professor (W2), Universität Konstanz.
    2012 - 2016: Aalto Science Institute Fellow, Aalto Ylliopisto, Helsingfors.
    2011 - 2012: Associate Fellow, Zukunftskolleg, Konstanz.
    2007 - 2011: Forskningsassistent, Goethe Universität Frankfurt.
    Tjeneste

    2023 - Norsk matematikkråd (leder)
    2022 - Styret for Abelprisen
    2022 - 2023 SIAM AG Algebraisk Geometri (offiser)
    2019 - 2020 Fakultetsstyret (NT Fakultet UiT)
    Konferanseorganisasjon

    ISSAC 2023 (Tromsø - leder av lokal organisasjon)
    Nasjonalt Matematikermøte 2022 (Tromsø - lokal organisasjonskomité)
    Baltic Way 2022 (Tromsø - leder av lokal organisasjonskomité)
    Nordisk Kombinatorisk Konferanse 2022 (Tromsø - lokal organisasjonskomité)
    Lie-Størmer Kolloquium 2020 (Rosendal - organisasjonskomité)
    MEGA 2021 (Tromsø - virtuelt - leder av lokal organisasjon)
    A^3 — Arctic Applied Algebra (Tromsø - leder av lokal organisasjonskomité)
    Applications of Real Algebraic Geometry 2014 (Aalto Universitet)
    Mathematics, Algorithms, and Proofs 2012 (organisasjonskomité)
    Organisering av mindre matematiske samlinger

    Kombinatoriske Hopf-algebraer og moderne Lie-teori med anvendelser (Sommerskole Nordfjordeid)
    Symmetri, stabilitet og interaksjoner med beregning (CIRM 2023)
    CATMI (Bergen - vitenskapelig komité)
    Temaer i reell og tropisk algebraisk geometri (Sommerskole Nordfjordeid)
    MFO-RIMS Tandem Workshop: Symmetrier på polynomidealer og varianter (MFO)
    Sommerskole i Algebraisk Statistikk (2018 UiT)