• Postdoctoral Researcher, Department of Mathematics, University of Ioannina, Greece. Jun. 2023 - Feb. 2024

• Research Associate, Department of Mathematics, Hong Kong Baptist University, Hong Kong. Apr. 2024 - Sep. 2024

• Adjunct Professor, Department of Informatics, Athens University of Economics and Business, Greece. Fall Semester. 2024

• Adjunct Professor, Department of Mathematics, University of Ioannina, Greece. Fall Semester. 2025

• B.Sc. (Mathematics), Department of Mathematics, University of Ioannina, Greece. Sep. 2013

• M.Sc. (Computational Mathematics and Informatics), Department of Mathematics, University of Ioannina, Greece. Dec. 2015

Advisor: Professor Dimitrios Noutsos.

Thesis Title: Preconditioned Conjugate Gradient Method for the Solution of Linear Toeplitz Systems.

• Ph.D.  (Mathematics), Department of Mathematics, University of Ioannina, Greece. Feb. 2022

Advisor: Professor Dimitrios Noutsos

Thesis Title: Krylov Subspace Methods for the Solution of Linear Toeplitz Systems.

• Numerical Analysis

• Computational Mathematics

• Numerical Linear Algebra

• Structured Matrices

• Preconditioning

• Partial Differential Equations

• D. Noutsos and G. Tachyridis, Band Toeplitz preconditioners for non-symmetric real Toeplitz systems by preconditioned GMRES method. J. Comput. Appl. Math., 373, 112250, (2020).

• D. Noutsos and G. Tachyridis, Band-times-circulant preconditioners for non-symmetric Toeplitz systems. BIT Numer. Math., 62(2), 561 - 590, (2022).

• T. Chaysri, A. Hadjidimos, D. Noutsos and G. Tachyridis, Band preconditioners for non-symmetric real Toeplitz systems with unknown generating function. In: Proceedings of the 25th International Conference on Circuits, Systems, Communications and Computers (CSCC), IEEE, (2021).

• T. Chaysri, A. Hadjidimos, D. Noutsos and G. Tachyridis, Band-times-circulant preconditioners for non-symmetric real Toeplitz systems with unknown generating function. East Asian J. Appl. Math., 12(2), 285-322, (2022). 

• G. Tachyridis and S. Y. Hon, An optimal preconditioned MINRES method for symmetrized multilevel block Toeplitz systems with applications. Numer. Linear Algebra Appl., 32(6), (2025). doi: 10.1002/nla.70047

• T. Chaysri, A. Hadjidimos, D. Noutsos and G. Tachyridis, Extensions of M−matrices and properties inherited by their Schur Complements. Linear Multilinear Algebra (under revision).

• 2nd Conference of Young Researchers in the Branches of Mathematical Science. Ioannina, Greece, Jun. 2018

• Numerical Analysis and Scientific Computation with Applications. Kalamata, Greece, Jul. 2018

• 13th Conference of the Euro-American Consortium for Promoting the Application of Mathematics in Technical and Natural Sciences. Albena, Bulgaria, Jun. 2021

• Workshop on Numerical Analysis in Honor of Emeritus Professor Dimitrios Noutsos. Ioannina, Greece, Apr 2023

• Numerical Analysis and Scientific Computation with Applications. Athens, Greece, Jul. 2023

• The 17th SIAM East Asian Section Conference. Macao SAR, China, Jun. 2024

• Numerical Analysis and Applications to Data Science. Athens, Greece, Apr. 2025

• Hong Kong Joint Universities Conference on Structured Matrices and Scientific Computing. Hong Kong SAR, China, Sep. 2025

• Greece and the European Union (European Social Fund-ESF) through the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020 in the context of the project “Krylov subspace methods and Perron-Frobenius theory” (MIS 5047643), Mar 2020 - Nov 2021

• Greece and the European Union (European Social Fund-ESF) through the Operational Programme Competitiveness, Entrepreneurship and Innovation 2014-2020 (EPAnEK) in the context of the project “Dioni: Computing Infrastructure for Big-Data Processing and Analysis” (MIS 5047222), Apr 2023 - Sep 2023

• Hong Kong RGC under grant 22300921, “A Fast Iterative Method for Ill-conditioned Toeplitz Systems”, Apr 2024 - Sep 2024

• Fall 2013-2018: Introduction to Programming, Department of Mathematics, University of Ioannina, Greece.

• Spring 2014-2019: Introduction to Computers, Department of Mathematics, University of Ioannina, Greece.

• Specialization Certificate in Computational Mathematics, University of Ioannina.

• Specialization Certificate in Mechanics, University of Ioannina.

• Certificate of Attendance and Successful Examination of Computer Science Courses, University of Ioannina.

• Special Education Certificate, University of the Aegean.

• ECDL Core Certicate.

• Coursera Certificate: Introduction to Mathematical Thinking, Stanford University.

• Coursera Certificate: Data Science Companion, Mathworks .