(every Monday, 10 am - 1 pm, M2/online)
Organizers: Ch. Psaroudakis, G. Raptis
The Algebra & Topology Seminar features research talks by invited speakers and members of the group, as well as seminar series devoted to selected research topics.
Topics covered in seminar series included tt-geometry, Brown and Adams representability, span categories and six-functor formalisms, and Koszul duality.
16/6/2026
• 14.00-15.00 D. Fink (Johannes Gutenberg University Mainz): A Structural Factorization of Ring Maps in Positive Characteristic
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8/6/2026
• 10.00-11.00 F. Yamauti (University of Regensburg): An invitation to the shape theory of topoi (Part I)
• 11.30-12.30 HOPEGA-AG: Recent developments in homological functional analysis
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25/5/2026
• 10.00-11.30 N. Müller (University of Mainz/AUTh): Report on recent advances in dg (co)algebras
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18/5/2026
• 10.00-11.00 A. Slaftsos (University of Padova): Varying exact structures in additive categories
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4/5/2026
• 10.00-11.00 HOPEGA-AG: Recent developments in dg (co)algebras and Koszul duality
• 11.30-12.30 K. Kartas (University of Münster): Tame Banach rings
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27/4/2026
• 10.00-11.00 S. Afentoulidis (Bar-Ilan University): An introduction to the Representation Theory of complex semi-simple Lie algebras, Part II
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30/3/2026
• 10.00-11.00 M. Karakikes (NKU Athens): Homological aspects of equivariant triangulated categories via separability
• 11.30-12.30 B. Cnossen (University of Regensburg): Construction of six-functor formalisms
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23/3/2026
• 10.00-11.00 P. Kostas (AUTh): Remarks on the global dimension of dg algebras
• 11.30-12.30 N. Müller (University of Mainz/AUTh): Span categories and their uses (7): The six functors in topology
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18/3/2026
• 18.15-19.15 F. De Leger (NTU Athens): Sweedler theory for double categories
17/3/2026
• 12.15-13.15 F. De Leger (NTU Athens): A-infinity algebras, Stasheff associahedron and Massey products
16/3/2026
• 10.00-11.00 F. De Leger (NTU Athens): Koszul duality for operads
• 11.30-12.30 A. Mustata (University of Copenhagen): Q-Shaped Derived Categories, Part 2
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9/3/2026
• 10.00-11.00 A. Mustata (University of Copenhagen): Q-Shaped Derived Categories, Part 1
• 11.30-12.30 A. Hayash (AUTh): Span categories and their uses (6): Universality of the span category, Part II
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2/3/2026
• 13.00-14.00 Ch. Psaroudakis (AUTh): Cleft Extensions of Triangulated Categories
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9/2/2026
• 10.00-11.00 HOPEGA-AG: Thinking about a theorem of Evens and Culler, Part II
• 11.30-12.30 N. Müller (University of Mainz/AUTh): Span categories and their uses (5): Universality of the span category, Part I
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2/2/2026
• 10.00-11.00 G. Raptis (AUTh): Thinking about a theorem of Evens and Culler
• 11.30-12.30 D. M. Carpena (University of Barcelona): Span categories and their uses (4): Universal biadjointable functors
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26/1/2026
• 10.00-11.30 N. Müller (University of Mainz/AUTh): Span categories and their uses (3): Review, examples and applications of Mackey 2-functors
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19/1/2026
• 10.00-11.00 O. Giatagantzidis (AUTh): Homological aspects of cyclic Nakayama algebras via minimal zero paths
• 11.30-12.30 M. Karakikes (NKU Athens): Span categories and their uses (2): Mackey 2-functors
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12/1/2026
• 10.00-11.00 K. M. Rahul (University of Bonn): Transferring structures on triangulated categories via metric techniques
• 11.30-12.30 Ch. Psaroudakis (AUTh): Span categories and their uses (1): Bicategories of spans
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15/12/2025
Workshop: Algebra & Geometry Day in Thessaloniki
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8/12/2025
• 10.00-11.00 P. Kostas (AUTh): Classical Brown and Adams representability (after Neeman)
• 11.30-12.30 G. Raptis (AUTh): Higher (n-categorical) Brown representability
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1/12/2025
• 10.00-11.00 D. M. Carpena (University of Barcelona): Classical and oo-categorical Brown-Adams representability
• 11.30-12.30 Ch. Verasdanis (AUTh): tt geometry (7)
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24/11/2025
• 10.00-11.00 G. Raptis (AUTh): What is a stable n-category?
• 11.30-12.30 Ch. Psaroudakis (AUTh): tt geometry (6): Stratification in tensor triangular geometry
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10/11/2025
• 10.00-11.00 I. Emmanouil (NKU Athens): Compactly generated tt-categories of Gorenstein projective modules over infinite groups
• 11.30-12.30 Ch. Verasdanis (AUTh): tt geometry (5)
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3/11/2025
• 10.00-11.00 P. Giagtzoglou (AUTh): Persistent modules
• 11.30-12.30 Ch. Verasdanis (AUTh): tt geometry (4)
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20/10/2025
• 10.00-11.00 M. Lupini (University of Bologna): Phantom extensions of modules
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13/10/2025
• 10.00-11.00 F. Andriopoulos (University of Chicago): From non-commutative to commutative world: variations of Hochschild homology
• 11.30-12.30 M. Karakikes (NKU Athens): tt geometry (3): Supports and filtrations
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6/10/2025
• 11.30-12.30 Ch. Psaroudakis (AUTh): tt geometry (2): Supports and filtrations
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29/9/2025
• 10.00-11.00 Ch. Psaroudakis (AUTh): Regular triangulated categories
• 11.30-12.30 P. Kostas (AUTh): tt geometry (1): The spectrum of prime ideals
(every Thursday evening, M2/online)
The Homotopical Algebra Seminar features learning seminar series on selected topics in homotopical algebra and higher category theory.
Spring Semester 2026
Reading Course: "Introduction to Infinity-Categories" (tutors: A. Hayash, N. Müller, G. Raptis).
Winter Semester 2025/26
Seminar: "Model Categories" (organizers: P. Kostas, N. Müller, G. Raptis). See here for the seminar schedule.
(every Friday, 3 - 6 pm, M2/online)
Organizers: M. Maridakis, V. Patzalis, G. Raptis
The Topology & Geometry Seminar features research talks by invited speakers and members of the group, as well as seminar series devoted to selected research topics.
The Seminar has focused especially on topics and research perspectives related to bounded cohomology. Other topics covered included Morse theory, the h-principle and representation theory of Lie algebras.
18/6/2026
• 16.00–17.00 S. Pedretti (University of Bologna): Non-singular and Symmetric Simplicial Sets
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12/6/2026
• 15.00–16.00 I. Gkeneralis (AUTh): How Much of the Homeomorphism Type Is Determined in Toric Topology?
• 16.30–17.30 F. Yamauti (University of Regensburg): An Invitation to the Shape Theory of Topoi, Part II
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5/6/2026
• 14.00–15.00 P. Batakidis (AUTh): Topological and Delzant-Type Classification of Quaternionic Torus Actions
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29/5/2026
• 15.00–16.00 HOPEGA-AG: Report on Recent Advances in Bounded Cohomology
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22/5/2026
• 15.00–16.00 Ch. Psaroudakis (AUTh): An Introduction to the Representation Theory of Complex Semisimple Lie Algebras, Part V
• 16.30–18.00 HOPEGA-AG: Thinking about the Category O
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15/5/2026
• 15.00–16.00 S. Afentoulidis (Bar-Ilan University): An Introduction to the Representation Theory of Complex Semisimple Lie Algebras, Part IV
• 16.30–18.00 N. Fachravar (AUTh): An Introduction to Grothendieck Topologies and Sheaves
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8/5/2026
• 15.00–16.00 P. Capovilla (University of Cyprus): Aspherical 4-Manifolds with Positive Euler Characteristic
• 16.30–18.00 S. Afentoulidis (Bar-Ilan University): An Introduction to the Representation Theory of Complex Semisimple Lie Algebras, Part III
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24/4/2026
• 15.00–16.00 S. Afentoulidis (Bar-Ilan University): An Introduction to the Representation Theory of Complex Semisimple Lie Algebras, Part I
• 16.30–18.00 M. Maridakis (AUTh): Bounded Cohomology and Simplicial Volume (21): The Milnor–Wood Inequality, Part II
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3/4/2026
• 15.00–16.00 HOPEGA-AG: The h-Principle and Its Applications (4)
• 16.30–18.00 M. Maridakis (AUTh): Bounded Cohomology and Simplicial Volume (20): The Milnor–Wood Inequality
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27/3/2026
• 15.00–16.00 S. Pedretti (University of Bologna): Introduction to Gromov's Multicomplexes
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (19): A Homotopical Approach to Gromov's Vanishing Theorem and Generalizations
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20/3/2026
• 15.00–16.00 HOPEGA-AG: The h-Principle and Its Applications (3)
• 16.30–18.00 M. Maridakis (AUTh): Bounded Cohomology and Simplicial Volume (19): The Milnor–Wood Inequality, Part I
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13/3/2026
• 15.00–16.00 HOPEGA-AG: The h-Principle and Its Applications (2)
• 16.30–18.00 HOPEGA-AG: Bounded Cohomology and Simplicial Volume (18½): More on Bounded Products
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6/3/2026
• 15.00–16.00 HOPEGA-AG: The h-Principle and Its Applications (1): Introduction
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (18): Why Bounded Products Matter, Part II
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27/2/2026
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (17): Why Bounded Products Matter, Part I
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13/2/2026
• 15.00–18.00 HOPEGA-AG: Bounded Cohomology and Simplicial Volume (16): Exact Categories of G-Banach Spaces and Their Derived Categories
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6/2/2026
• 15.00–18.00 HOPEGA-AG: Bounded Cohomology and Simplicial Volume (15): Exact Categories of Banach Spaces, Derived Categories, and t-Structures
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30/1/2026
• 15.00–18.00 HOPEGA-AG: Bounded Cohomology and Simplicial Volume (14½): Research Perspectives in Homological Functional Algebra
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23/1/2026
• 15.00–16.00 M. Moraschini (University of Bologna): Introduction to Boundedly Acyclic Groups
• 16.30–18.00 P. Kostas (AUTh): Bounded Cohomology and Simplicial Volume (14): Preliminaries to Homological Functional Algebra (continued)
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16/1/2026
• 15.00–16.30 P. Kostas (AUTh): Bounded Cohomology and Simplicial Volume (13): Preliminaries to Functional Homological Algebra
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19/12/2025
• 15.00–16.00 A. Hayash (AUTh): Constructible Sheaves of Categories, Animated Path Algebras, and n-Affineness
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (12): Bounded Acyclicity of Homeo(ℝⁿ), Part II
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12/12/2025
• 15.00–16.00 P. Giagtzoglou (AUTh): Stability of Persistence
• 16.30–18.00 V. Patzalis (AUTh): Bounded Cohomology and Simplicial Volume (11): Bounded Acyclicity of Homeo(ℝⁿ), Part I
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5/12/2025
• 15.00–16.00 M. Maridakis (AUTh): Bounded Cohomology and Simplicial Volume (10): Negative Curvature and Simplicial Volume
• 16.30–18.00 M. Maridakis (AUTh): Bounded Cohomology and Simplicial Volume: The Proportionality Principle
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28/11/2025
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (9): Homeo(S¹) (after Monod–Nariman)
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21/11/2025
• 15.00–16.00 G. Raptis (AUTh): What Is... Catastrophe Theory?
• 16.30–18.00 V. Patzalis (AUTh): Bounded Cohomology and Simplicial Volume (8): Additivity of Simplicial Volume
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14/11/2025
• 15.00–16.00 M. Maridakis (AUTh): Introduction to Morse Theory (7)
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (7): The Mapping Theorem
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7/11/2025
• 15.00–16.00 A. Valaristou (AUTh): Introduction to Morse Theory (6)
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (6): Amenability in Bounded Cohomology
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31/10/2025
• 15.00–16.00 R. Tsiavou (AUTh): Introduction to Morse Theory (5)
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (5)
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24/10/2025
• 15.00–16.00 R. Tsiavou (AUTh): Introduction to Morse Theory (4)
• 16.30–18.00 G. Raptis (AUTh): Bounded Cohomology and Simplicial Volume (4)
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17/10/2025
• 15.00–16.00 M. Maridakis (AUTh): Introduction to Morse Theory (3)
• 16.30–18.00 V. Patzalis (AUTh): Bounded Cohomology and Simplicial Volume (3): Simplicial Volume
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10/10/2025
• 15.00–16.00 M. Maridakis (AUTh): Introduction to Morse Theory (2)
• 16.30–18.00 V. Patzalis (AUTh): Bounded Cohomology and Simplicial Volume (2): Quasimorphisms, Bounded Cohomology of Topological Spaces
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3/10/2025
• 15.00–16.00 M. Maridakis (AUTh): Introduction to Morse Theory (1)
• 16.30–18.00 V. Patzalis (AUTh): Bounded Cohomology and Simplicial Volume (1): Bounded Cohomology of Groups