Rete ITaliana di Approssimazione

Research ITalian network on Approximation (RITA)

The "Research ITalian network on Approximation (RITA)" groups several italian numerical analysts working on Multivariate Approximation. In this website we collect all research topics and activites of RITA members and institutions.


Statute and guidelines


At the moment the network is among the following institutions and people:

  • Department of Mathematics "Tullio Levi-Civita", University of Padova

Topics: kernel methods; meshless approximation and applications; polynomial, trigonometric and rational interpolation and approximation; quadrature and cubature formulas; approximation theory in medical imaging; mathematical system modelling from data; high performance computing

International collaborations: B. Bauman (Lawrence Livermore National Laboratory), J.-P. Calvi (Univ. of Toulouse III), K. Hormann (Univ. of Lugano), A. Iske (Univ. of Hamburg), A. Kroo (Hungarian Academy of Sciences, Budapest), P. Leopardi (Australian Gov. Bureau of Meteorology, Melbourne), N. Levenberg (Indiana Univ., Bloomington), R. Schaback (Univ. of Goettingen), K. Usevich (CNRS, Grenoble), Y. Xu (Univ. of Oregon, Eugene)

Visiting 2022: A. M. Acu (University of Sibiu) 19/2-12/3 2022

Visiting 2020: L. Bialas-Ciez (Jagellonian Univ., Cracow) and M. Baran (Pedagogical Univ., Cracow) 12-22/2 2020

Visiting 2019: A. Kroo (Hungarian Academy of Sciences, Budapest) 1-30/6 2019, A. P. Peron (University of São Paulo, São Carlos) 14-25/1 2019, L. Plaskota (Univ. of Warsaw) 9-18/1 2019 [phd-course], A. Weinmann (Darmstadt Univ. of Applied Sciences) 13-31/5 2019


Visiting 2018: N. Levenberg (Indiana Univ., Bloomington) 27/4-5/5 2018, M. Slawinski (Memorial University of Newfoundland) 18-22/6 2018


Visiting 2017: A. Kroo (Hungarian Academy of Sciences, Budapest) 8/1-8/4 2017, A. Neisy (Allameh Tabataba'i Univ.) 19/7-22/8 2017, W. Erb (Univ. of Hawaii, Honolulu) 24-28/7 2017, A. Weinmann (Univ. of Darmstadt) 24-28/7 2017, M. Buhmann (Univ. of Giessen) 30/10-4/11 2017, H. Wendland (Univ. of Bayreuth) 6-27/11 2017 [seminar-abstract]

  • Department of Computer Science, University of Verona

Topics: polynomial, trigonometric and rational interpolation and approximation; matrix exponential approximation by interpolation

International collaborations: T. Bloom (Univ. of Toronto), J.-P. Calvi (Univ. of Toulouse III), K. Hormann (Univ. of Lugano), N. Levenberg (Indiana Univ., Bloomington), A. Ostermann and S. Rainer (Univ. of Innsbruck), S. Waldron (Univ. of Auckland)

Visiting 2017: A. Ostermann (Univ. of Innsbruck) 24/4-5/5 2017

  • Center for Information and Communication Technology - Fondazione Bruno Kessler

  • Department of Mathematics and Applications, University of Milano - Bicocca

Topics: kernel methods; meshless approximation and applications; subdivision schemes; wavelets; frames; mathematical signal processing

International collaborations: F. Arandiga and R. Donat (Univ. of Valencia), C. Rabut (INSA Toulouse), T. Sauer (Univ of Passau), R. Schaback (Univ. of Goettingen)

  • Department of Mathematics "Giuseppe Peano", University of Torino

Topics: kernel methods; meshless approximation and applications; approximation theory in medical imaging; approximation algorithms for biological models

International collaborations: S. Demertzis (Cardiocentro Ticino, Lugano), G.E. Fasshauer (Colorado School of Mines, Golden), M. Haque (Univ. of Nottingham), E. Larsson (Uppsala Univ.), H. Malchow (Osnabrueck Univ.), M. Mayr (FH Wiener Neustadt), M.J. McCourt (SigOpt, Inc., San Francisco), B. Quatember and W. Recheis (Univ. of Innsbruck), H. Wendland (Univ. of Bayreuth)

  • Department of Mathematics, University of Genova

Topics: approximation theory; kernel methods; surface reconstruction for inverse problems; medical and astronomical imaging

  • Department of Mathematics, Alma Mater Studiorum University of Bologna

Topics: geometric modeling; numerical methods for CAGD; refinable functions; subdivision schemes; image analysis and segmentation

International collaborations: G. Albrecht (Univ. of Medellin), M. Charina (Univ. of Wien), N. Dyn (Tel Aviv Univ.), V. Hernandez Mederos and J. Estrada Sarlabous (ICIMAF, Havana), J.-L. Merrien (INSA Toulouse), J. Stockler (TU Dortmund), M. Unser (EPFL Lausanne), J. Yoon (Ewha W. Univ. Seul)

  • Department of Industrial Engineering, University of Firenze

Topics: subdivision schemes; wavelets; frames; mathematical signal processing

International collaborations: M. Charina (Univ. of Wien), N. Dyn (Tel Aviv Univ.), J.-L. Merrien (INSA Toulouse), T. Sauer (Univ. of Passau), J. Stockler (TU Dortmund), M. Unser (EPFL Lausanne), J. Yoon (Ewha W. Univ. Seul)

Visiting 2018: D. Labate (Houston Univ.) 15/5-13/6 2018

Visiting 2017: S. Huning (TU Graz) 10/9-24/12 2017, S. Lopez Urena (Univ. of Valencia) 1/10-24/12 2017, J.-L. Merrien (INSA Toulouse) 22-28/1 2017

  • School of Science and Technology (Matematics division), University of Camerino

Topics: numerical methods for PDE; polynomial interpolation and approximation; spectral methods; image analysis; inverse problems; classification and regression problems; Support Vector Machines; numerical methods for integral equations

International collaborations: Y. Li (Liaocheng Univ.), G. Manzini (Los Alamos National Laboratory), S. Pickl (Universität der Bundeswehr München), L. Qiao (Liaocheng Univ.), N. Sorin (Universität der Bundeswehr München)

  • Department of Mathematics and Computer Science, University of Perugia

Topics: approximation theory by sampling-type operators, approximation by neural network type operators, approximation theory in medical imaging, mathematical image processing, signal theory, mathematical methods for civil and energetic engineering

International collaborations: T. Acar (Selçuk Univ., Selcuklu), J. Appel (Wuerzburg Univ.), P.L. Butzer and R.L. Stens (Aachen), L. Coroianu (Oradea Univ.), H. Karsli (Abant Izzet Baysal Universitesi), E. Lyflyand (Bar-llan Univ.), J. Musielak (Poznan), M. Skopina (S. Petersburg State Univ.), S. Tikhonov (Barcellona)

Visiting 2018: M. Skopina (S. Petersburg State Univ.) 14-21/1 2018

Visiting 2017: S. Tikhonov (Barcellona), E. Lyflyand (Bar-llan Univ.) 14-20/2 2017

  • Department of Basic and Applied Sciences for Engineering, University of Roma "La Sapienza"

Topics: subdivision schemes; wavelets; mathematical signal processing; fractional differential problems; undetermined inverse problems; multiscale analysis; time-frequency transforms; image processing; information theory

International collaborations: D. Calvetti and F. Somersalo (Case Western Reserve Univ., Cleveland), A. Kokaram (Trinity College, Dublin), B. Piccoli (Rutgers Univ., USA), I. Selesnick (New York Univ.)

Visiting 2019: D. Calvetti and F. Somersalo (Case Western Reserve Univ., Cleveland) 14/1-14/2 2019

  • Section of Mathematics, Uninettuno University, Roma

    • staff members: Clemente Cesarano, Paolo Emilio Ricci, Renato Spigler [section-link]

Topics: special functions in approximation theory; non-trigonometric Fourier analysis; polynomial and trigonometric approximation; quadrature and cubature formulas; eigenvalues approximation; geometrical models; fractional differential problems; numerical methods for integral equations; approximation algorithms for biological models

International collaborations: P. Agarwal (ANAND, Jaipur, India), N. Cakic (Univ. of Beograd, Serbia), D. Caratelli (Tomsk Polytechnic Univ., Tomsk, Russia), J. Gielis (Univ. of Antwerp, Belgium), M.X. He (Nova Southeastern Univ., Ft. Lauderdale, FL, U.S.A.), S. Khan (Aligarh Muslim Univ., India), S. Pinelas (Academia Militar, Amadora, Purtugal), H.M. Srivastava (Univ. of Victoria, Canada), I. Tavkhelidze (Tbilisi State Univ., Georgia), L. Vazquez Martinez (Univ. Complutense)

  • Departments of Mathematics and Physics, University of Campania "L. Vanvitelli", Caserta

Topics: kernel methods; meshless approximation and applications; mathematical signal processing; spline and rational interpolation and approximation


International collaboration: K. Hormann (Univ. of Lugano)


Visiting 2020: K. Hormann (Univ. of Lugano) 07/01 2020

  • Departments of Mathematics and Applications "R. Caccioppoli" and Agricultural Sciences, University of Naples Federico II

Topics: kernel methods; meshless approximation and applications; mathematical signal processing; high performance computing


International collaborations: G. Mei (University of Geoscience, Beijing), P. Assari (Bu-Ali Sina University)

Visiting 2019: D. Calvetti and E. Somersalo (Case Western Reserve Univ., Cleveland) 18/05-20/06 2019 [Data-Mining-course]

Visiting 2018: D. Calvetti and E. Somersalo (Case Western Reserve Univ., Cleveland) 02-21/05 2018

  • CNR National Research Council of Italy - IAC Institute, Naples

Topics: meshless approximation and applications; numerical methods for integral equations; polynomial interpolation and approximation; quadrature and cubature formulas; singular problems; wavelets


International collaborations: F. Filbir (Helmholtz Munich), P. Junghanns (TU Chemitz), M. Van Barel (KU Leuven)


Visiting 2019: F. Filbir (Helmholtz & Technische Universität München) 28/2-9/3 2019 [seminar-abstract-1], [seminar-abstract-2]

  • Department of Mathematics, University of Salerno

Topics: collocation/Runge-Kutta methods for ODEs, FDEs and VIEs; parallel numerical methods; model reduction methods; exponentially fitted methods for oscillatory problems; numerical methods for stochastic VIEs

International collaborations: Z. Jackiewicz (Arizona State Univ.), L.Gr. Ixaru (Institute of Physics and Nuclear Engineering, Bucharest), Ch. Lubich (Univ. of Tuebingen), F. Mohammadi and L. Moradi (Univ. of Hormozgan, Iran), S. Shahmorad and Y. Talaei (Univ. of Tabriz, Iran)

Visiting 2019: L. Moradi (Univ. of Hormozgan, Iran) 9/7/2018-5/8/2019 and 27/9-24/10 2019, J. Butcher (Univ. of Auckland, New Zealand) 31/7-4/08 2019, H. Podhaisky (Univ. of Halle, Germany) 22/9-30/9 2019, L. Ixaru (Institute of Physics and Nuclear Engineering, Bucharest, Romania) 17/11-26/11 2019

Visiting 2018: D. Cohen (Umea Univ.) 2-7/2/2018, Z. Jackiewicz (Arizona State Univ.) 8-13/7 2018

Visiting 2017: L.Gr. Ixaru (Institute of Physics and Nuclear Engineering, Bucharest), 14-18/12 2017

  • Department of Mathematics, University of Bari "A. Moro"

Topics: positive approximation processes; approximation problems for semigroups of operators and evolution equations


International collaborators: T. Acar (Selçuk Univ., Selcuklu), P. Garrancho (Univ. of Jaen), I. Rasa (Technical Univ. of Cluj-Napoca)

  • Department of Mathematics and Physics "E. De Giorgi", University of Salento

Topics: approximation by positive operators; approximation of semigroups; rate of convergence; evolution problems

International collaborations: T. Acar (Selçuk Univ., Selcuklu), I. Rasa (Technical Univ. of Cluj-Napoca)

  • Department of Mathematics, Computer Science and Economy, University of Basilicata, Potenza

Topics: numerical methods for integral equations; polynomial interpolation and approximation; quadrature and cubature formulas; singular problems; positive approximation processes; approximation problems for semigroups of operators and evolution equations

International collaborations: T. Acar (Selcuk Univ., Selcuklu), T. Diogo and P. Lima (Instituto Superior Técnico, Lisbon), P. Garrancho (University of Jaén), P. Junghanns (TU Chemnitz), G.V. Milovanovic (Serbian Academy of Sciences, Beograd), I. Rasa (Technical Univ. of Cluj-Napoca), J. Szabados (Hungarian Academy of Sciences, Budapest)

  • Department of Mathematics and Computer Science, University of Cagliari

Topics: numerical methods for Fredholm and Volterra integral equations, quadrature and cubature formulae, inverse problems, polynomial interpolation, and approximation

International collaborations: D. Dukic (University of Belgrade, Serbia), T. Diogo and P. Lima (Instituto Superior Tecnico, Lisbon), R. Mutavdzic (University of Belgrade, Serbia), L. Reichel (Kent State University, Ohio, US), M. Spalevic (University of Belgrade, Serbia)

  • Department of Mathematics and Computer Science, University of Calabria, Cosenza

Topics: meshless approximation and applications; polynomial and rational interpolation and approximation; quadrature and cubature formulas; collocation and spectral methods for IVPs and BVPs; bisection-exclusion algorithms

International collaborations: K. Hormann (Univ. of Lugano), O. Nouisser (Univ. Ibn Tofail, Kenitra, Marocco), W.M. Abd-Elhameed (Cairo University)

Visiting 2018: T. Sauer (Univ. of Passau) 11/1 2018 [seminar-abstract], B. Zerroudi (Ibn Tofail Univ., Kenitra) 8-20/4 2018

  • Department of Information Engineering, Infrastructure and Sustainable Energy, Mediterranean University of Reggio Calabria

Topics: subdivision schemes; wavelets; frames; mathematical signal processing

International collaborations: M. Charina (Univ. of Wien), M. Holschneider (Univ. of Potsdam), T. Sauer (Univ. of Passau)

Visiting 2019: M. Charina (Univ. of Vienna) and T. Sauer (Univ. of Passau) 9-17/1 2019

Visiting 2018: T. Sauer (Univ. of Passau) 7-13/1 2018

  • Department of Industrial and Digital Innovation, University of Palermo

Topics: kernel methods; meshless approximation and applications; wavelet and multiresolution analysis; high performance computing; BVPs; approximation algorithms for biological models

International collaborations: G.E. Fasshauer (Colorado School of Mines, Golden), F.M. Hilker (Osnabrueck Univ.), M.J. McCourt (SigOpt, Inc., San Francisco)

Visiting 2019: G.E. Fasshauer (Colorado School of Mines, Golden) 12-18/6 2019


  • Department MIFT, University of Messina

Topics: wavelets; mathematical signal processing; image restoration

International collaborations: M. Holschneider (Potsdam Univ.)


RITA abroad