Department of Mathematics, University of Zagreb

Ljiljana Arambašić, Damir Bakić, Aleksandar Bulj, Luka Cigler, Tonći Crmarić, Ilja Gogić, Pavle Goldstein, Boris Guljaš, Dijana Ilišević, Ivana Katić, Biserka Kolarec, Vjekoslav Kovač, Hrvoje Kraljević, Filip Martinović, Bruno Predojević, Ivan Puljiz, Rajna Rajić, Jelena Rupčić, Mateo Tomašević, Anđa Valent

Ljiljana Arambašić, Ilja Gogić, Dijana Ilišević, Vjekoslav Kovač

C*-algebras, Hilbert C*-modules, frames, wavelets, elementary operators, associative and nonassociative rings and algebras, various types of orthogonality, linear preservers, K-theory, semigroups, Fourier analysis, ...

Typically Thursdays 12-14 at the Department of Mathematics, room 109 (or online)

• Luka Cigler, Application of the theory of Hilbert C*-modules in Gabor analysis, 16.10.2025. (Thursday) at 12:15 in 109 (PMF-MO)

• Shobu Shiraki, Mini Course: The Restriction Conjecture, October-November 2025.

TALKS (2024/2025):

• Keith Rogers (ICMAT), Improved bounds for the Kakeya conjecture using semialgebraic geometry, 17.10.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Dijana Ilišević, Surjective isometries of C*-algebras, 7.11.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Lina Oliveira (University of Lisbon), Projections and operator symmetry in Hilbert space, 5.12.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Bruno Predojević, Lp contractivity for semigroups generated by elliptic operators, 12.12.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Mateo Tomašević, Jordan homomorphisms of structural matrix algebras (PhD thesis defense), 19.12.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Graduate students of PMF-MO, 27.2.2025 (Thursday) at 12:00 in 109 (PMF-MO):
  • Ivan Bošnjak, Vedran Cifrek, and Marija Ćorić: Characterizations of Reflexivity and James Space
  • Paula Horvat, Duje Perković, and Matko Petričić: Study of the Dual of l-infinity
  • Hana Bilić, Tin Pavlić, and Luka Šimek: Applications of Hilbert Space Theory to Wavelets
• Shobu Shiraki, Pointwise Convergence Problems, Geometry, and Orthonormal Systems, 24.4.2025. (Thursday) at 12:15 in 109 (PMF-MO)
• Graduate students of PMF-MO, 15.7.2025 (Tuesday) at 13:30 in 109 (PMF-MO)
  • Hana Bilić: The spectral theorem for a bounded normal operator
  • Vedran Cifrek: Representations of C*-algebras and the Gelfand-Naimark theorem
  • Duje Perković: The Wold-von Neumann decomposition 

TALKS (2023/2024):

• Panagiotis Batakidis (Aristotle University of Thessaloniki), Old and new about the Atiyah class, 24.10.2023. (Tuesday) at 12 in 109 (PMF-MO)
• Fani Petalidou (Aristotle University of Thessaloniki), Dorfman Connections of Courant algebroids and the Atiyah class of Manin pairs, 26.10.2023. (Thursday) at 12 in 109 (PMF-MO)
• Denis Husadžić, UHF-algebras, 7.12.2023. at 12 in 109 (PMF-MO)
• Vjekoslav Kovač, Almost almost-orthogonality of operators and applications, 21.3.2024. (Thursday) at 12:15 in 109 (PMF-MO)
• Ilijas Farah (York University, Toronto), Strongly self-absorbing C*-algebras and logic,  23.4.2024. (Tuesday) at 17:15 in 201 (PMF-MO)
• Armin Schikorra (University of Pittsburgh), Div-curl estimates and harmonic maps: local and nonlocal, 9.5.2024. (Thursday) at 15 in A102 (PMF-MO)
• Mateo Tomašević, Jordan homomorphisms of structural matrix algebras (obrana teme doktorske disertacije), 16.5.2024. (Thursday) at 12:00 in 109 (PMF-MO)
• Peter Šemrl (Institute of Mathematics, Physics and Mechanics, Ljubljana), On the fundamental theorem of chronogeometry,
  16.5.2024. (Thursday) at 13:00 in 109 (PMF-MO)
• Fuzhen Zhang (Nova Southeastern University, SAD), Some Eigenvalue and Singular Value Inequalities, 20.5.2024. (Monday) at 13:00 in A101 (PMF-MO)
• Vjekoslav Kovač, Alice and Bob play the convergence game and help Paul, 23.5.2024. (Thursday) at 12:15 in A102 (PMF-MO)
• Matt W. Larson (Stanford University), Low rank matrix completion and tensor codes, 13.6.2024. (Thursday) at 12:15 in 201 (PMF-MO)

TALKS (2022/2023):

• Luka Cigler, Application of the theory of the Hilbert C*-modules in the Gabor analysis, 22.3.2023.
• Aleksandar Bulj, Estimates for Homogeneous Fourier Multipliers and Multiparameter Maximal Fourier Restriction, 4.4.2023.
• Bruno Predojević, Combinatorial hypercubes in the plane, 31.5.2023.
• Ilja Gogić, Characterizations of homogeneous C*-algebras, 21.6.2023.
• Ivan Puljiz, Spectral theory of Dirichlet forms and spaces on graphs, 14.9.2023.
• Tonći Crmarić, Solitons of the Kadomtsev-Petviashvili equation and cluster algebras, 21.9.2023.
• Vjekoslav Kovač, What do we know about plane colorings?, 26.9.2023.
• Mateo Tomašević, Jordan homomorphisms of parabolic algebras, 28.9.2023.

TALKS (2021/2022):

• Aleksandar Bulj, Fourier transform and multi-parameter maximal estimates, 29.9.2022.
• Gregor Dolinar, Preserving the distance on the set of probability measures, 17.09.2022. 
• Bojan Kuzma, Spectrum preservers on unbounded operators, 17.09.2022.
• Dijana Ilišević, Isometries and contractions - a brief overview, 17.09.2022.
• Janko Marovt, Preservers of partial orders, 17.9.2022.
• Aleksandar Bulj, Asymptotic behavior of L^p estimates for a class of multipliers with homogeneous unimodular symbols, 9.6.2022. 
• Bruno Predojević, Bourgain's simplex theorem,  26.1.2022. 
• Vjekoslav Kovač, Semigroups generated by complex elliptic operators and Orlicz space estimates,  19.1.2022. 
• Matija Livaić, C*-algebraic formalism of quantum mechanics II,  28.10.2021. 
• Matija Livaić, C*-algebraic formalism of quantum mechanics, 21.10.2021. 

TALKS (2020/2021):

• Mateo Tomašević, Homomorphisms of matrix algebras, 23.6.2021.
• Kristina Škreb, The matrix-weighted Hardy-Littlewood maximal function is unbounded, 16.6.2021. u 13:15 (online)
• Aleksandar Bulj, Tensor product in problem solving, 19.5.2021. u 13:15 (online)
• Oliver Dragičević, Trilinear embedding theorem for elliptic partial differential operators in divergence form with complex coefficients, 12.5.2021. u 13:15 (online)
• Ilja Gogić, The Dixmier property and weak centrality for C*-algebras: local approach III, 28.4.2021. u 13:15 (online)
• Ilja Gogić, The Dixmier property and weak centrality for C*-algebras: local approach II, 21.4.2021. u 13:15 (online)
• Ilja Gogić, The Dixmier property and weak centrality for C*-algebras: local approach I, 14.4.2021. u 13:15 (online)
• Ljiljana Arambašić, Operators preserving strong Birkhoff-James orthogonality in B(H), 31.3.2021. u 13:15 (online)
• Ljiljana Arambašić, Symmetrized strong Birkhoff-James orthogonality in commutative C*-algebras, 24.3.2021. u 13:15 (online)

TALKS (2019/2020):

• Luka Žunić, When is the canonical contraction from the central Haagerup tensor product of a C*-algebra to completely bounded maps isometric? II, 30.9.2020.
• Luka Žunić, When is the canonical contraction from the central Haagerup tensor product of a C*-algebra to completely bounded maps isometric? I, 29.9.2020.
• Boris Guljaš, Characterization and description of Hilbert modules with the complementing property II, 4.3.2020.
• Boris Guljaš, Characterization and description of Hilbert modules with the complementing property I, 26.2.2020.
• Mateo Tomašević, C*-algebras with the CQ-property II, 30.10.2019.
• Mateo Tomašević, C*-algebras with the CQ-property I, 9.10.2019.

TALKS (2018/2019):

• Damir Bakić, Gabor frames as weak modular frames, 25.9.2019.
• Edward Poon (Embry-Riddle Aeronautical University, USA), Unitary orbit preservers, 23.9.2019.
• Workshop: Operator Days, 31.1.-1.2.2019. (program) 
  • Lajoš Molnar (University of Szeged and Budapest University of Technology and Economics), Thompson isometries of positive definite cones in C*-algebras and applications, 31.1.2019. 
  • Peter Šemrl (University of Ljubljana), Isometries of Grassmann spaces, 1.2.2019.
  • Ljiljana Arambašić, The minimal redundancy property of frames and signal reconstruction, 1.2.2019.
  • Ilja Gogić, The CB-norm approximation of generalized skew derivations by elementary operators, 1.2.2019.
  • Dijana Ilišević, When is a finite sum of box operators on a JB*-triple a hermitian?, 1.2.2019.
• Diana Stoeva (Austrian Academy of Sciences, Vienna), Frame multipliers, sufficient conditions for inversion and formulas for the inverse operator, 11.1.2019. 12:00
• Damir Bakić, Weak frames for Hilbert C*-modules and Gabor systems III, 5.12.2018.
• Damir Bakić, Weak frames for Hilbert C*-modules and Gabor systems II, 28.11.2018.
• Damir Bakić, Weak frames for Hilbert C*-modules and Gabor systems I, 21.11.2018.
• Vjekoslav Kovač, On convergence and the Fourier analysis restriction problem, 17.10.2018.
• Karmen Grizelj, Regularity of L^1(G), II, 3.10.2018.

TALKS (2017/2018):

• Karmen Grizelj, Regularity of L^1(G), 26.9.2018.
• Damir Bakić, The dual of the standard Hilbert C*-module, 19.9.2018. 
• Diogo Oliveira e Silva, Sphere packings and the uncertainty principle, 4.7.2018.
• Boris Guljaš, Orthogonal complements in Hilbert C*-modules, 6.6.2018.
• Bojan Kuzma (University of Primorska, Slovenia), Matrices with extremal commutants and beyond, 7.3.2018.
• Luka Žunić, Elementary and local elementary operators on C*-algebras, 1.3.2018.
• Ilja Gogić, When are continuous C(X)-algebras finitely generated?, 1.3.2018.
• Tomislav Berić, Frame duality and excess, 1.3.2018.
• Michael Frank, On the existence of frames and *-frames, 27.2.2018. 10:00
• Pavle Goldstein, Equivalences for C*-correspondences and Pimsner algebras, 21.2.2018.
• Tomislav Berić, Heil-Ramanathan-Topiwala conjecture, 29.11.2017.
• Dijana Ilišević, Stability of the Wigner equation - a singular case, 22.11.2017.
• Dijana Ilišević, On superstability of the Wigner equation, 15.11.2017.
• Hrvoje Šikić, BMO prostori i dekompozicija težina, 14.11.2017. u 16:00, 201

TALKS (2016/2017):

• Mario Stipčić, Extensions of Bessel sequences to a pair of dual frames, 27.9.2017.
• Ljiljana Arambašić, Operators preserving the strong Birkhoff-James orthogonality in B(H), 17.5.2017.
• Rajna Rajić, The Roberts orthogonality and the Davis-Wielandt shell, 10.5.2017.
• Jelena Rupčić, Nonlinear Hausdorff-Young inequality II, 3.5.2017.
• Jelena Rupčić, Nonlinear Hausdorff-Young inequality, 19.4.2017.
• Tomislav Berić, Numerical range and the Davis-Wielandt shell of operators, 22.3.2017.
• Vjekoslav Kovač, Democratic systems of translates on LCA groups, 7.2.2017. u 14:00
• Jelena Rupčić, Nonlinear SU(1,1)-valued Fourier transform, 14.12.2016.

TALKS (2015/2016):

• Ilja Gogić, Generalized two-sided multiplications and the second Čech cohomology,7.9.2016.
• Luka Žunić, The inner derivations and the primitive ideal space of a C*-algebra 2, 20.4.2016.
• Luka Žunić, The inner derivations and the primitive ideal space of a C*-algebra 1, 23.3.2016.
• Damir Bakić, Reconstruction of signals with erasures IV: full spark and totally postive matrices, 9.3.2016.
• Ljiljana Arambašić, Reconstruction of signals with erasures III, 10.2.2016.
• Branimir Ćaćić (Texas A&M University), Sketches of noncommutative differential geometry, 21.12.2015., 14:00
• Cristina Benea (University of Nantes), AKNS systems and iterated Fourier integrals, 16.12.2015.
• Damir Bakić, Reconstruction of signals with erasures II, 18.11.2015.
• Damir Bakić, Reconstruction of signals with erasures I, 11.11.2015.
• Ljiljana Arambašić, Frames in Hilbert C*-modules V, 28.10.2015.
• Ljiljana Arambašić, Frames in Hilbert C*-modules IV, 21.10.2015.
• Diana Rupčić, The Laplace transform on the cones of lattice-structured Banach spaces II, 7.10.2015.

TALKS (2014/2015):

• Pavle Goldstein, Higher rank Cuntz-Krieger C*-algebras, 30.9.2015.
• Ilja Gogić, Uniform closure of two-sided multiplications and phantom line bundles, 23.9.2015.
• Damir Bakić, Frames in Hilbert C*-modules III, 29.4.2015.
• Ilja Gogić, CB-norm aproximation of derivations by elementary operators, 22.4.2015.
• Vjekoslav Kovač, UMD-spaces, 8.4.2015.
• Damir Bakić, Frames in Hilbert C*-modules II, 25.3.2015.
• Damir Bakić, Frames in Hilbert C*-modules I, 11.3.2015.
• Ljiljana Arambašić, On three concepts of orthogonality in Hilbert C*-modules, 12.11.2014.

• Zagreb Workshop on Operator Theory, July 3 and 4, 2014. 

TALKS (2013/2014):

• Ana Laštre, Parseval multivawelets, 24.6.2014.
• Ana Laštre, Parseval multivawelets, 23.6.2014.
• Luka Žunić, Banach bundles and  C(X)-locally convex modules, 11.6.2014.
• Damir Bakić, Dual frames in Hilbert spaces, 09.04.2014.
• Ilja Gogić, Classification of homogeneous C*-algebras, 12.03.2014.
• Josipa Čuka, Bicircular projections, 18.12.2013.
• Hrvoje Šikić, Stability of Schauder bases, 12.11.2013.
• Tomislav Berić, Parseval frames II, 30.10.2013.
• Tomislav Berić, Parseval frames I, 23.10.2013.
• Tomislav Berić, Excesses of frames, 16.10.2013.

TALKS  (2012/2013):

• Ilja Gogić, Stability problem for a local multiplier algebra, 11.09.2013.
• Ilja Gogić, C(X)-algebras and C(X)-valued conditional expectations of finite index, 03.07.2013.
• Tomislav Berić, Parseval frames in Hilbert spaces, 19.06.2013.
• Tomislav Berić, Iterations of the generalized Gram-Schmidt orthogonalization of frames, 12.06.2013.
• Hrvoje Šikić, Democratic system of translates II, 29.05.2013.
• Hrvoje Šikić, Democratic system of translates I, 28.05.2013.
• Ljiljana Arambašić, The best approximation problem in Hilbert C*-modules II, 24.04.2013.
• Rajna Rajić, The best approximation problem in Hilbert C*-modules I, 17.04.2013.
• Pavle Goldstein, Characterisation of generalized flow equivalence relation, 21.11.2012.
• Tomislav Berić, Perturbations of Hilbert space frames II, 31.10.2012.
• Bojan Kuzma (University of Primorska, Koper, Slovenia), On maps which do not increase the spectrum of difference of matrices, 26.10.2012.
• Tomislav Berić, Perturbations of Hilbert space frames I, 17.10.2012.

TALKS (2011/2012):

• Ivana Slamić, Systems of translates and redundancy II, 25.09.2012.
• Ivana Slamić, Systems of translates and redundancy I, 18.09.2012.
• Ivana Geček Tuđen, Bimodular derivation, 11.07.2012.
• Damir Bakić, Scaling sets and orthonormal wavelets with integer dilations, 27.06.2012.
• Rajna Rajić, Birkhoff-James orthogonality in Hilbert C*-modules II, 28.3.2012.
• Ljiljana Arambašić, Birkhoff-James orthogonality in Hilbert C*-modules I, 21.3.2012.
• Ilja Gogić, Derivations implemented by local multipliers II, 15.2.2012.
• Ilja Gogić, Derivations implemented by local multipliers I, 8.2.2012.
• Radomir Lončarević, Separation of convex sets in normed spaces, 21.12.2011.
• Pavle Goldstein, Isomorphism of continuous fields of Cuntz algebras, 14.12.2011.
• Radomir Lončarević, Geometric form of the Hahn-Banach theorem, 07.12.2011.

TALKS (200?-2011)

• Ljiljana Arambašić, Hilbert C*- modules over finitedimensional C*-algebras, 06.07.2011.
• Daniel Eremita (University of Maribor), The Lower Socle and Finite Rank Elementary Operators, 15.06.2011.
• Tomislav Berić, Generalized Gram-Schmidt orthogonalization generating all Parseval frames, 18.05.2011.
• Ilja Gogić, Topologically finitely centrally generated C*-algebras, 11.5.2011.
• Ilja Gogić, Topologically finitely generated Hilbert C(X)-modules III, 27.04.2011.
• Morten Nielsen (Aalborg University, Denmark), Stability of Finitely Generated Shift Invariant Spaces, 20.04.2011.
• Ana Laštre, Commuting mappings,13.04.2011.
• Ilja Gogić, Topologically finitely generated Hilbert C(X)-modules II, 23.03.2011.
• Ilja Gogić, Topologically finitely generated Hilbert C(X)-modules I, 16.03.2011.
• Pavle Goldstein, Quasi-free actions of finite groups on O_\infty II, 02.03.2011.
• Pavle Goldstein, Quasi-free actions of finite groups on O_\infty I, 23.02.2011.
• Ilja Gogić, On a class of noncommutative branched coverings, 02.02.2011.
• Ilja Gogić, Banach bundles of finite type, 08.12.2010.
• Conference: Operators, Spaces, Algebras, Modules, March 1-4, 2010.
• Hrvoje Šikić, Schauder bases and shift-invariant spaces 1, 2 
• Ljiljana Arambašić, Gram matrix in Hilbert C*-modules
• Damir Bakić, Kaczmarz algorithm and Bessel sequences
• Ilja Gogić, The Dauns-Hofmann theorem
• Ilja Gogić, Some applications of the Dauns-Hofmann theorem
• Ilja Gogić, On homomorphic image of the center of a C*-algebra
• Ilja Gogić, On closedness of the set of inner derivations of a C*-algebra
• Ljiljana Arambašić, Characterizations of some classes of Hilbert C*-modules
• Dijana Ilišević, Perturbation of the Wigner equation in Hilbert C*-modules
• Damir Bakić, Dimension functions and a method of construction of orthonormal wavelets
• Rajna Rajić, Characterization of the case of equality in the triangle inequality in Hilbert C*-modules
• Ljiljana Arambašić, Operator triangle inequality and the case of equality
• Srđan Maksimović, Construction of orthonormal wavelets from scaling sets
• Ilja Gogić, Elementary operators and C*-algebras of finite central tensor rank
• Ilja Gogić, Derivations which are inner as completely bounded maps
• Tomislav Berić, Derivations on B(H)
• Lajos Molnar (University of Debrecen, Hungary), Isometries of some metric spaces of functions and operators
• M.V. Wickerhauser (Washington University, St. Louis), Discrete wavelet transforms in practice 
• Hrvoje Šikić, Schauder bases and shift-invariant spaces 1, 2