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

• • staff members: Stefano De Marchi, Wolfgang Erb, Francesco Marchetti, Fabio Marcuzzi, Federico Piazzon, Alvise Sommariva, Marco Vianello

  • post-doc: Giacomo Elefante, Maryam Mohammadi

  • phd students: Cinzia Bandiziol, Mohammad Karimnejad Esfahani

  • external collaborators: Davide Poggiali

Topics: meshless approximation theory and algorithms; numerical cubature and polynomial approximation; mathematical system modelling from data; high performance computing; multivariate polynomial approximation; kernel-based approximation; mapped bases; barycentric rational approximation; medical image analysis and reconstruction; generalized Bernstein operators; kernel methods and machine learning 

International collaborations: A. M. Acu (University of Sibiu), B. Bauman (Lawrence Livermore National Laboratory), J.-P. Berrut (University of Fribourg), L. Bialas-Ciez (Jagiellonian University Krakow), M. Buhmann (University of Giessen), J.-P. Calvi (Univ. of Toulouse III), K. Hormann (Univ. della Svizzera Italiana), A. Iske (Univ. of Hamburg), A. Kroo (Hungarian Academy of Sciences, Budapest), E. Larsson (University of Uppsala), G. Meurant (CEA), P. Leopardi (Australian Gov. Bureau of Meteorology, Melbourne), N. Levenberg (Indiana Univ., Bloomington), M. Mohammadi (Kharazmi University Teheran), I. Rasa (Technical University Cluj-Napoca), R. Schaback (Univ. of Goettingen), K. Usevich (CNRS, Grenoble), H. Wendland (University of Bayreuth), Y. Xu (Univ. of Oregon, Eugene) 

Visiting 2023: M. Mohammadi (Kharazmi University) 5/1-6/2 2023, A. M. Acu ("Lucian Blaga" University of Sibiu) and I. Rasa (Technical University of Cluj-Napoca) 16-22/1 2023, L. Bialas-Ciez (Jagellonian University of Cracow) 16-24/1 2023

Visiting 2022: A. M. Acu ("Lucian Blaga" University of Sibiu) 19/2-12/3 2022, A. Iske (University of Hamburg) 17-22/12 2022

Visiting 2020: L. Bialas-Ciez (Jagellonian University of Cracow) and M. Baran (Pedagogical University of 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

• • staff members: Len Bos, Marco Caliari

  • phd student: Franco Zivcovich

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

• Department of Environmental Sciences, Informatics and Statistics (DAIS), Ca' Foscari University of Venezia

• • staff member: Gabriele Santin

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

• • staff member: Milvia Rossini

Topics: meshfree approximation, kernel based methods, approximation theory, wavelets, mathematica signal and image 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

• • staff members: Roberto Cavoretto, Alessandra De Rossi, Incoronata Notarangelo, Ezio Venturino, Alberto Viscardi

  • phd student: Francesca Acotto, Sandro Lancellotti, Adeeba Haider

Topics: kernel methods; meshless approximation and applications; approximation theory in medical imaging; adaptive methods for PDEs ; approximation algorithms for biological models; artificial intelligence and machine learning algorithms; traffic models for sustainable mobility; subdivision schemes; design of curves and surfaces; weighted polynomial approximation; numerical methods for integral equations; quadrature formulas; orthogonal polynomials 

International collaborations: S. Demertzis (Cardiocentro Ticino, Lugano), M. Esmaeilbeigi (Malayer Univ.), G.E. Fasshauer (Colorado School of Mines, Golden), A. Guessab (Université de Pau et des Pays de l'Adour), M. Haque (Univ. of Nottingham), K. Hormann (Univ. della Svizzera Italiana), P. Junghanns (Chemnitz University of Technology), E. Larsson (Uppsala Univ.), S. López-Ureña (Univ. de Vaència), H. Malchow (Osnabrueck Univ.), M. Mayr (FH Wiener Neustadt), M.J. McCourt (SigOpt, Inc., San Francisco), G. V. Milovanovic (Serbian Academy of Sciences and Arts), B. Quatember and W. Recheis (Univ. of Innsbruck), J. Stöckler (TU Dortmund),H. Wendland (Univ. of Bayreuth), J. Szabados and P. Vértesi (Alfréd Rényi Institute of Mathematics, Hungarian Academy of Sciences), L. Szili (Lorànd Eötvös University and Budapest University of Technology and Economics)

Visiting 2023: K. Hormann (Università della Svizzera Italiana), M. Marva Ruiz (universidad de Alcalá), A. Guessab (Université de Pau et des Pays de l’Adour) 

Visiting 2022: D. Leviatan (Tel Aviv University), A. Guessab (Université de Pau et des Pays de l'Adour) 14-23/04

• Dipartimento di Scienze Matematiche "G.L. Lagrange" (DISMA), Politecnico di Torino

  • staff members: Emma Perracchione

Topics: approximation theory; inverse problems; kernels; machine learning 

• Department of Mathematics, University of Genova

• • staff member: Cristina Campi

  • phd-students: Isabella Cama 

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

• Department of Mathematics, Alma Mater Studiorum University of Bologna

• • staff member: Lucia Romani

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

International collaborations: G. Albrecht (Univ. of Medellin), 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

• • staff member: Costanza Conti

Topics: subdivision,splines, approximation theory, regression analysis 

International collaborations: A. Cuyt (Universiteit Antwerpen), N. Dyn (Tel Aviv Univ.), S. López-Ureña (Univ. de Vaència), 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

• • staff members: Renato De Leone, Nadaniela Egidi, Lorella Fatone, Pierluigi Maponi

  • post-doc: Josephin Giacomini

  • phd students: Lorenza Spadoni, Filippo Santarelli, Elisa Marcelli

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

• • staff members: Laura Angeloni, Carlo Bardaro, Danilo Costarelli, Ilaria Mantellini, Gianluca Vinti, Luca Zampogni

  • post-doc: Marco Seracini

  • phd students: Eleonora De Angelis, Mariarosaria Natale, Michele Piconi, Arianna Travaglini

Topics: approximation by sampling-type operators; neural network operators and their applications; approximation theory in medical imaging; mathematical image processing; signal theory; mathematical methods for civil and energetic engineering; real analysis; functional analysis; operators in Orlicz spaces; self-adjoint operators; direct and inverse spectral theory; water waves; discrete and integral operator; Voronovskaja formula 

International collaborations: T. Acar (Selçuk Univ., Selcuklu), J. Appel (Wuerzburg Univ.), P.L. Butzer and R.L. Stens (Aachen), L. Coroianu (Oradea Univ.), U. Kadak (Gazi Univ.), H. Karsli (Abant Izzet Baysal Universitesi), E. Lyflyand (Bar-llan Univ.), N. Merentes (Universidad Central de Venezuela), J. Musielak (Poznan), S. Reinwand (University of Wurzburg, Germany), G. Schmeisser (Friedrich-Alexander-University of Erlangen-Nürnberg), M. Skopina (S. Petersburg State Univ.), S. Tikhonov (Barcellona), M. A. Valera-Lòpez (Universidad Central de Venezuela) 

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"

• • staff members: Vittoria Bruni, Laura Pezza, Francesca Pitolli, Domenico Vitulano

Topics: subdivision schemes; wavelets; mathematical signal processing; fractional differential problems; undetermined inverse problems; multiscale analysis; time-frequency transforms; image processing; information theory; numerical solution of inverse problems; randomized methods; numerical methods for fractional differential problems 

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]

  • external collaborators: William Ramirez, Adnan Shannon 

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), R. Dmytryshynr (Vasyl Stefanyk Precarpathian National University), J. Gielis (Univ. of Antwerp, Belgium), M.X. He (Nova Southeastern Univ., Ft. Lauderdale, FL, U.S.A.), S. Jimenez (UPM), S. Khan (Aligarh Muslim Univ., India), O. Moaaz (Mansoura University, Egypt), S. Pinelas (Academia Militar, Amadora, Purtugal), H.M. Srivastava (Univ. of Victoria, Canada),  I. Tavkhelidze (Tbilisi State Univ., Georgia), L. Vazquez Martinez (Univ. Complutense)

Visiting 2022: P. Agarwal

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

• • staff members: Rosanna Campagna

Topics: Numerical resolution of inverse problems; splines functions; numerical stability of rational barycentric operators.

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

• • staff member: Salvatore Cuomo

Topics: kernel methods; meshless approximation and applications; mathematical signal processing; high performance computing; mutlivariate data analysis; mathematics for AI 

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

• • staff members: Maria Rosaria Capobianco, Woula Themistoclakis

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

• • staff member: Dajana Conte

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"

• • staff member: Mirella Cappelletti Montano

Topics: approximation theory, semigroups theory, functional analysis 

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

• • staff member: Michele Campiti

Topics: Korovkin approximation theory, evolution problems, semigroup theory

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

• • staff members: Maria Carmela De Bonis, Concetta Laurita, Vita Leonessa, Donatella Occorsio, Maria Grazia Russo

  • professor emeritus: Giuseppe Mastroianni

  • phd students: Domenico Mezzanotte, Valeria Sagaria, Anna Lucia Lagauardia 

  • external collaborators: Giada Serafini

Topics: numerical methods for integral equations; polynomial interpolation and approximation; quadrature rules; approximation of integral transforms; operator theory; singular problems; positive approximation processes; approximation problems for semigroups of operators and evolution equations; numerical treatment of BIE; potential theory applied to several BVPs

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), M. Stanic and T. Tomovic (University of Kagrujevac) 

• Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari

  • staff member: Iulia Martina Bulai

Topics: Eco-epidemiological mathematical models, Wastewater bioremediation modelling, Electrical activity and Ca+ dynamics in endocrine cells modelling, Slow/fast bifurcation analysis, Mathematical models applied to cancer, Graph signal processing

• Department of Mathematics and Computer Science, University of Cagliari 

  • staff member: Luisa Fermo

Topics: Integral equations, quadrature and cubature formulae, inverse problems 

International collaborations: D. Djukic (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

• • staff members: Francesco Dell'Accio, Filomena Di Tommaso, Anna Napoli

  • phd students: Federico Nudo

Topics: meshless approximation and applications; scattered data approximation; polynomial interpolation; quadrature and cubature formulas; mixed interpolation and regression; bisection-exclusion algorithms; initial and boundary value problems; collocation methods; polynomials and their applications in approximation theory 

International collaborations: W.M. Abd-Elhameed (Cairo University), A. Guessab (Université de Pau et des Pays de l'Adour), K. Hormann (Univ. of Lugano), O. Nouisser (Univ. Ibn Tofail, Kenitra, Marocco)

Visiting 2022: A. Guessab (Université de Pau et des Pays de l'Adour) 

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

• • staff member: Mariantonia Cotronei

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

• • staff member: Elisa Francomano

  • external collaborator: Marta Paliaga

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

  • staff member: Luigia Puccio

Topics: wavelets; mathematical signal processing; image restoration

International collaborations: M. Holschneider (Potsdam Univ.)

RITA abroad

• Emiliano Cirillo (Lausanne), Gaspare Da Fies (Aberystwyth)