Schedule and abstracts
DATES
- Arrival: 07/07/2024
18:00 - Welcome Reception and Registration - Talks: 08/07 - 12/07
- Excursion: 10/07
- Conference Dinner: 11/07
- Departure: 13/07
SCIENTIFIC PROGRAMME
- The scientific programme consists of invited plenary talks, invited semi-plenary talks and contributed talks.
- Contributed talks will be 30mins long (including 5mins for discussion), semi-plenary ones 45mins (including 5mins for discussion), and plenary ones 60mins (including 10mins for discussion).
The schedule is provisional and subject to changes.
All lecture rooms have a beamer projector and chalkboards that can be used alongside.
You can download the full programme with abstracts here: booklet.
FULL SCHEDULE
invited plenary talks invited semi-plenary talks contributed talksSunday | Monday | Tuesday | Wednesday | Thursday | Friday | |
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08:15 | Registration | |||||
08:45-09:00 | Opening | |||||
09:00-10:00 | Tholen | Soukup | Kwietniak | Bonet | Walters-Wayland | |
10:00-10:30 | Coffee Break | |||||
10:30-11:30 | Parallel Sessions |
Parallel Sessions |
Parallel Sessions |
Parallel Sessions |
Parallel Sessions |
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11:30-12:30 | Verberne | |||||
12:30-14:15 | Lunch | |||||
14:15-15:00 | Dahmen | Reggio | Zhang | Carvalho | Excursion | Guzman | Arrieta | Parallel Sessions |
|
15:00 | Parallel Sessions |
Parallel Sessions |
Parallel Sessions |
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15:15-16:15 | Pinsker | |||||
16:15 | Closing | |||||
16:30-17:00 | Coffee Break | Coffee Break | ||||
17:00-18:00 | Parallel Sessions |
Parallel Sessions |
Parallel Sessions |
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18:00-19.30 | Welcome Reception |
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19:30-20:30 | Conference Dinner |
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DAILY SCHEDULE
Monday, July 08, 2024
Plenary Talk Room Pedro Nunes (ground floor) | |
09:00 - 10:00 |
From distances and operator norms to normed categories
AbstractFor the study of normed vector spaces or of similar structures one may not like to be
confined from the outset to the consideration of morphisms that respect the algebraic and
metric structure of the objects of interest as smoothly as the 1-Lipschitz linear operators
do. At least initially it may be preferable to work in a categorical environment with
less perfectly behaved morphisms, but that instead comes with an operator norm which,
amongst all linear maps, will then help to pinpoint classes of topologically or metrically
interesting morphisms, such as the bounded or the 1-Lipschitz operators. Having such general categorical environment, the first questions we may want to ask are: What does Cauchy convergence mean? What is completeness with respect to such a notion of convergence, and do completions exist? Is there a “mother category” which, in normed category theory, may play the role that Set plays in ordinary category theory? Are there protagonist normed categories, and is the category of normed vector spaces and linear operators amongst them? Are there unexpected examples, and how do the notions designed for large categories fare when applied to an individual space considered as a small normed category, like a metric space? In this talk we will try to address all of these questions. While we base our approach on the notion of normed category as suggested by Lawvere [1], unlike several later articles on the subject we do not amend his axioms but follow rather strictly the original design of the normed structure as an enrichment. Indeed, the guidance of enriched category theory has helped us finding answers to some of the questions posed. Although we allow norms to be quantale-valued, rather than just real-valued, and thereby substantially increase the range of potential applications, the talk should remain understandable for an audience with basic knowledge of category theory, including that of adjunctions. This presentation was preceded by the talks [3, 4]. Other than to the original work [1], we also refer to the article [2] which has influenced our choice of examples. For further literature and all mathematical details not covered in the talk, we refer to the paper [5]. References: [1] F.W. Lawvere, Metric spaces, generalized logic, and closed categories, Rend. Sem. Mat. Fis. Milano 43, 135–166, 1973. Republished in: Reprints in Theory Appl. Categories 1, 2002. [2] W. Kubis, Categories with norms, 2017. https://arxiv.org/pdf/1705.10189 . [3] W. Tholen, Quantale-weighted Categories, Talk given at: 106th Peripatetic Seminar on Sheaves and Logic, Brno, May 2022. http://www.math.muni.cz/ bourkej/PSSL106.html . [4] D. Hofmann, Cauchy completeness for normed categories, Talk given at: Coimbra Category Seminar, October 2023. https://www.mat.uc.pt/ categ/pcs14/slides/Hofmann.pdf . [5] M.M. Clementino, D. Hofmann and W. Tholen, Cauchy convergence in V-normed categories, 2024. https://arxiv.org/abs/2404.09032. |
10:00 - 10:30 |
Coffee Break
|
Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
10:30 - 11:00 |
An invitation to cellular-Lindelöf spaces
|
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 |
Weak containment for topological actions
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Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 |
Adherence determined convergences
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11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topology and Categories Room 2.5 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 |
Monoidal closedness of complete residuated lattice-valued generalized convergence groups
|
12:00 - 12:30 |
Free distributive and extensive categorical structures
|
12:30 - 14:15 |
Lunch
|
Semi-plenary Talk Room Pedro Nunes (ground floor) | |
14:15 - 15:00 |
Isometry groups as topological groups
Abstract Metric geometry is an active field of mathematical research with numerous impressive
results and tons of open questions. This fascinating area of mathematics is connected to
the world of topological algebra via the isometry group:
Given a metric space (X, d), the group of isometric bijections Iso(X, d) can be endowed
with a natural topology, turning it into a topological group. It can be shown that every
complete topological group can be realized as the isometry group of a suitable metric space,
so the isometry group Iso(X, d) of a general metric space (X, d) can be very complicated
in general. Therefore, it is a natural question under which additional assumptions on the
space (X, d) we obtain more well-behaved topological groups as Iso(X, d).
There are many results in that direction, for example Iso(X, d) is a Lie group if (X, d)
is a Riemannian manifold, endowed with its standard distance function.
In this talk, I will give a survey about isometry groups and how geometric properties
of the space correspond to topological and algebraic properties of the group. I will also
address an interesting open question about certain infinite-dimensional metric spaces and
pro-Lie groups (in the sense of Hofmann/Morris). |
Semi-plenary Talk Room 17 de Abril (ground floor) | |
14:15 - 15:00 |
Game comonads: logical and homotopical aspects
Abstract
Game comonads were introduced in [1, 5] to provide a categorical approach to finite
model theory and descriptive complexity, which typically focus on logic fragments with
a finite amount of logical resources, such as finite-variable logics or logics with bounded
quantifier rank, and the corresponding combinatorial parameters of (relational) structures.
In many cases, equivalence in these logic fragments can be captured in a syntax-free way
by means of model-comparison games, such as Ehrenfeucht–Fraïssé and pebble games. The key insight underlying game comonads is that collections of plays in these games can be naturally organised into endofunctors on categories of relational structures that carry the structure of comonads, and their coalgebras encode both the corresponding logic fragments and the combinatorial parameters. This idea has proved to be very robust and the whole pattern, covering a range of resource-bounded logics, has been axiomatised at a general categorical level in [2, 3]. These results have led to new connections between two areas within logic in computer science that have largely been disjoint: finite model theory and descriptive complexity, and semantics and categorical structures of computation. In this talk, I will give an overview of the main ideas underpinning game comonads, with an emphasis on their: (i) Logical aspects, including a categorical view on homomorphism counting results [6, 7] and equi-resource homomorphism preservation theorems [4]; (ii) Homotopical aspects, including the use of upgrading arguments in preservation theorems, akin to small object arguments in abstract homotopy, and a homotopical view of modal logic and the Łoś-Tarski preservation theorem [8]. References:
[2] Abramsky, S.; Reggio, L. Arboreal categories and resources. 48th International Colloquium on Automata, Languages, and Programming (ICALP), 2021, 115:1–115:20. [3] Abramsky, S.; Reggio, L. Arboreal categories: An axiomatic theory of resources. Logical Methods in Computer Science, 2023, 14:1–14:36. [4] Abramsky, S.; Reggio, L. Arboreal categories and equi-resource homomorphism preservation theorems. Annals of Pure and Applied Logic, 2024, 103423. [5] Abramsky, S.; Shah, N. Relating structure and power: Comonadic semantics for computational resources. 27th EACSL Annual Conference on Computer Science Logic (CSL), 2018, 2:1–2:17. [6] Dawar A.; Jakl, T; Reggio, L. Lovász-type theorems and game comonads. 36th Annual ACM/IEEE Symposium on Logic in Computer Science (LiCS), 2021. [7] Reggio, L. Polyadic sets and homomorphism counting. Advances in Mathematics, 2022, 108712. [8] Reggio, L. A model category for modal logic. https://arxiv.org/abs/2310.12068. |
Session: Set-theoretic Topology Room Pedro Nunes (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Dynamics and Continuum Theory Room 2.4 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
Session: Set-Theoretic Topology Room 2.4 (2nd floor) | |
16:00 - 16:30 | |
Session: Topology in Logic and Computer Science Room 2.5 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 |
Divergence measures over the set of persistence diagrams
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16:30 - 17:00 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
17:00 - 17:30 | |
17:30 - 18:00 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
17:00 - 17:30 | |
17:30 - 18:00 |
Tuesday, July 09, 2024
Plenary Talk Room Pedro Nunes (ground floor) | |
09:00 - 10:00 |
Resolvable and irresolvable spaces
AbstractA topological space is resolvable if it can be partitioned into two dense subsets.
Otherwise, it is termed irresolvable. A topological space X is considered maximally resolvable if it is ∆(X)-resolvable, where ∆(X) is the minimum cardinality of a non-empty open subset. Examples of maximally resolvable spaces include metric, ordered, compact, or pseudo-radial spaces. However, there exist countable, dense-in-itself, irresolvable spaces. In this presentation we investigate the resolvability of different classes of topological spaces, such as Lindelöf, pseudocompact, countably compact, and monotone normal spaces. We investigate what can we say on the resolvability of product of spaces. Although the problems seems to be purely topological, we will encounter many statements that are independent of ZFC, and we can not avoid mentioning large cardinals as well. References: [1] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. On resolvability of products. Fund. Math. 260 (2023), no. 3, 281–295. [2] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. On the resolvability of Lindelöf-generated and (countable extent)-generated spaces. Topology Appl. 259 (2019), 267–274. [3] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. Coloring Cantor sets and resolvability of pseudocompact spaces. Comment. Math. Univ. Carolin. 59 (2018), no. 4, 523–529. [4] Soukup, Lajos ; Stanley, Adrienne. Resolvability in c.c.c. generic extensions. Comment. Math. Univ. Carolin. 58 (2017), no. 4, 519–529. [5] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. Regular spaces of small extent are -resolvable. Fund. Math. 228 (2015), no. 1, 27–46. [6] Soukup, Dániel T. ; Soukup, Lajos. Partitioning bases of topological spaces. Comment. Math. Univ. Carolin. 55 (2014), no. 4, 537–566. [7] Juhász, István ; Shelah, Saharon ; Soukup, Lajos. Resolvability vs. almost resolvability. Topology Appl. 156 (2009), no. 11, 1966–1969. [8] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. Resolvability and monotone normality. Israel J. Math. 166 (2008), 1–16. [9] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. Resolvability of spaces having small spread or extent. Topology Appl. 154 (2007), no. 1, 144–154. [10] Juhász, István ; Soukup, Lajos ; Szentmiklóssy, Zoltán. D-forced spaces: a new approach to resolvability. Topology Appl. 153 (2006), no. 11, 1800–1824. |
10:00 - 10:30 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Sessions: Topology and Order - Topology in Logic and Computer Science Room 2.5 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
12:30 - 14:15 |
Lunch
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Semi-plenary Talk Room Pedro Nunes (ground floor) | |
14:15 - 15:00 |
Topological structures on real-enriched categories
Abstract
This talk concerns extensions of Scott topology to real-enriched categories. A real-
enriched category is a category with real numbers as enrichment. The definition is as
follows. For each continuous t-norm & on the unit interval [0, 1], V = ([0, 1], &, 1) is a
complete and symmetric monoidal closed category. A V-category is then a pair (X, α),
where X is a set and α : X × X → [0, 1] is a function such that (i) α(x, x) = 1 for all x ∈ X; and (ii) α(y, z) & α(x, y) ≤ α(x, z) for all x, y, z ∈ X. Such V-categories are called real-enriched categories. If we interpret the value α(x, y) as the truth degree that x precedes y, then (i) is reflexivity and (ii) is transitivity. So, real-enriched categories may be viewed as many-valued ordered sets. Since the quantale ([0, ∞]op, +, 0) is isomorphic to ([0, 1], ·, 1), quasi-metric spaces are natural examples of real-enriched categories. We focus on topological structures of real-enriched categories, including classical topo- logical structures and V-approach structures. A V-approach structure on a set is a map δ : X × 2X → [0, 1] such that for all x ∈ X and all A, B ∈ 2X, (A1) δ(x, {x}) = 1; (A2) δ(x, ∅) = 0; (A3) δ(x, A ∪ B) = δ(x, A) ∨ δ(x, B); (A4) δ(x, A) ≥ (infb∈B δ(b, A))& δ(x, B). The value δ(x, A) is interpreted as the truth degree that x is close to A. So, a V-approach structure is a many-valued topology, a V-valued topology to be precise. Scott topology is an important topology on partially ordered sets, it makes every directed subset converge to its supremum. In this talk we discuss extensions of Scott topology to the realm of real-enriched categories. References: [1] M.M. Bonsangue, F. van Breugel, J.J.M.M. Rutten, Generalized metric space: completion, topology, and powerdomains via the Yoneda embedding, Theoretical Computer Science 193 (1998) 1-51. [2] R.C. Flagg, R. Kopperman, Continuity spaces: Reconciling domains and metric spaces, Theoretical Computer Science 177 (1997) 111-138. [3] R.C. Flagg, P. Sünderhauf, The essence of ideal completion in quantitative form, Theoretical Computer Science 278 (2002) 141-158. [4] R.C. Flagg, P. Sünderhauf, K.R. Wagner, A logical approach to quantitative domain theory, Topology Atlas Preprint No. 23, 1996. http://at.yorku.ca/e/a/p/p/23.htm [5] P. Fletcher, W.F. Lindgren, Quasi-Uniform Spaces, Marcel Dekker Inc., New York and Basel, 1982. [6] G. Gierz, K.H. Hofmann, K. Keimel, J.D. Lawson, M. Mislove, D.S. Scott, Continuous Lattices and Domains, Cambridge University Press, Cambridge, 2003. [7] J. Goubault-Larrecq, Non-Hausdorff Topology and Domain Theory, Cambridge University Press, Cambridge, 2013. [8] J. Goubault-Larrecq, K.M. Ng, A few notes on formal balls, Logical Methods in Computer Science 13(4:18) (2017) 1-34. [9] G. Gutierres, D. Hofmann, Approaching metric domains, Applied Categorical Structures 21 (2013) 617-650. [10] P. Hájek, Metamathematics of Fuzzy Logic, Kluwer Academic Publishers, Dordrecht, 1998. [11] D. Hofmann, G.J. Seal, W. Tholen (eds.), Monoidal Topology: A Categorical Approach to Order, Metric, and Topology, Cambridge University Press, Cambridge, 2014. [12] E.P. Klement, R. Mesiar, E. Pap, Triangular Norms, Kluwer Academic Publishers, Dordrecht, 2000. [13] H. Lai, W. Tholen, Quantale-valued approach spaces via closure and convergence, Topology and its Applications 230 (2017) 599-620. [14] H. Lai, D. Zhang, G. Zhang, The saturated prefilter monad, Topology and its Applications 301 (2021) 107525. [15] F.W. Lawvere, Metric spaces, generalized logic, and closed categories, Rendiconti del Seminario Matématico e Fisico di Milano 43 (1973) 135-166. [16] W. Li, D. Zhang, Scott approach distance on metric spaces, Applied Categorical Structures 26 (2018) 1067-1093. [17] R. Lowen, Approach Spaces: the Missing Link in the Topology-Uniformity-Metric Triad, Oxford University Press, 1997. [18] R. Lowen, Index Analysis, Approach Theory at Work, Springer, 2015. [19] M. B. Smyth, Quasi-uniformities: Reconciling domains with metric spaces, in: Mathematical Foundations of Programming Language Semantics, Lecture Notes in Computer Science, vol 298, pp. 236-253, Springer, Berlin, 1988. [20] M. B. Smyth, Completeness of quasi-uniform and syntopological spaces, Journal of London Mathematical Society 49 (1994) 385-400. [21] K.R. Wagner, Liminf convergence in Ω-categories, Theoretical Computer Science 184 (1997) 61-104. [22] B. Windels, The Scott approach structure: an extension of the Scott topology for quantitative domain theory, Acta Mathematica Hungarica 88 (2000) 35-44. [23] J. Yu, D. Zhang, Continuous [0, 1]-lattices and injective [0, 1]-approach spaces, Fuzzy Sets and Systems 444 (2022) 49-78. |
Semi-plenary Talk Room 17 de Abril (ground floor) | |
14:15 - 15:00 |
Shift operators on Banach spaces
Abstract
This talk is about linear dynamics in infinite dimensional Banach spaces. Suppose one
takes a sequence of bidimensional matrices and, at each vector in ℓp(ℝ2), applies the matrices coordinatewise and then shifts the resulting sequence. What is the expected dynamics
of such a linear operator in ℓp(ℝ2)? Is it hyperbolic? Has it non-trivial recurrence? Does
it satisfy the shadowing property? I will present a recent joint work with Udayan Darji
and Paulo Varandas where we address these and analogous questions for a new family
of linear bounded invertible maps, which we call shift operators. This family comprises
weighted backward shifts and (up to linear conjugation) finite products of weighted shifts
and dissipative composition operators. I will illustrate the variety of dynamical properties
this family exibits, explain how we classify a large class of these shift operators and prove
that, for them, generalized hyperbolicity is equivalent to shadowing.
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Session: Set-theoretic Topology Room Pedro Nunes (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
Session: Set-theoretic Topology Room 2.4 (2nd floor) | |
16:00 - 16:30 | |
Session: Topology and Categories Room 2.5 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 |
Kuratowski convergence in approach spaces
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16:30 - 17:00 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
17:00 - 17:30 | |
17:30 - 18:00 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
17:00 - 17:30 |
Dynamics of weighted composition operators
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17:30 - 18:00 |
Wednesday, July 10, 2024
Plenary Talk Room Pedro Nunes (ground floor) | |
09:00 - 10:00 |
An anti-classification theorem for the topological conjugacy problem for Cantor minimal systems
AbstractThe isomorphism problem in dynamics dates back to a question of von Neumann from
1932: Is it possible to classify the ergodic measure-preserving diffeomorphisms of a compact
manifold up to isomorphism? Foreman, Rudolph and Weiss proved an anti-classification
theorem that rigorously explains why, in a certain sense, such a classification is impossible
[1]. We study a topological analogue of von Neumann's problem. Let Min(C) stand
for the Polish space of all minimal homeomorphisms of the Cantor set C. Recall that a
homeomorphism T : C → C is minimal if every orbit of T is dense in C. We say that S
and T in Min(C) are topologically conjugate if there is a homeomorphism h: C → C such
that S ◦ h = h ◦ T . We will discuss an anti-classification result, saying that it is impossible
to tell if two minimal Cantor set homeomorphisms are topologically conjugate using only
a countable amount of information and computation. We will explain, how to understand
such an anti-classification result and why it suffices to show that the topological conjugacy
relation of Cantor minimal systems treated as a subset of Min(C) × Min(C) is complete
analytic, so a non-Borel subset of Min(C) × Min(C). References: [1] Matthew Foreman, Daniel J. Rudolph, Benjamin Weiss, The conjugacy problem in ergodic theory. Ann. of Math. (2) 173 (2011), no. 3, 1529-1586. |
10:00 - 10:30 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
Session: Topology and Order Room 2.5 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
Plenary Talk Room Pedro Nunes (ground floor) | |
11:30 - 12:30 |
Pseudo-Anosov homeomorphisms
AbstractThe mapping class group is the group of orientation preserving homeomorphisms of a surface up to isotopy. In particular, the mapping class group encodes information about
the symmetries of a surface. The Nielsen-Thurston classification states that elements of the
mapping class group are of one of three types: periodic, reducible, and pseudo-Anosov.
In this talk, we will focus our attention on the pseudo-Anosov elements, which are the
elements of the mapping class group which mix the underlying surface in a complicated
way. In this talk, we will discuss both classical and new results related to pseudo-Anosov
mapping classes, as well as the connections to other areas of mathematics. References: [1] A. Bar-Natan and Y. Verberne. The grand arc graph. Mathematische Zeitschrift 305:2 (2024). [2] Y. Verberne. A contruction of pseudo-Anosov homeomorphisms using positive twists. Algebraic & Geometric Topology 23:4 (2023) 1601–1639. |
12:30 - 14:15 |
Lunch
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14:15 - 20:00 |
Excursion
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Thursday, July 11, 2024
Plenary Talk Room Pedro Nunes | |
09:00 - 10:00 |
Ergodic theory for operators and applications to generalized Cesàro operators
AbstractIn the first part of this lecture we will review classical results about power bounded
and mean ergodic operators acting on Banach and more general spaces. Theorems by
Eberlein, Yosida and Lin will be stated. Compactness plays an important role in these
results. Some new abstract results will be presented. They will be utilized to investigated
the behaviour of generalized Cesàro operators when acting on sequence spaces and spaces
of analytic functions on the disc of the complex plane. The generalized Cesàro operators Ct, for t ∈ [0, 1], acts from ℂℕ0 into itself (with ℕ0 := 0, 1, 2, ...) is given by Ctx := ( For t = 0 note that C0 is a diagonal operator and for t = 1 that C1 is the classical Cesàro averaging operator. These operators act continuously in many classical Banach sequence spaces such as ℓp, c0, c. In the setting of analytic functions Ct has the integral representation Ctf(0) := f(0) and Ctf (z) := for every f ∈ H(𝔻 ). References: [1] A. A. Albanese, J. Bonet, W. J. Ricker, Spectral properties of generalized Cesàro operators in sequence spaces. RACSAM 117 (2023), Article number 140. [2] A. A. Albanese, J. Bonet, W. J. Ricker, Generalized Cesàro operators in weighted Banach spaces of analytic functions with sup-norms. Collectanea Math. (to appear). |
10:00 - 10:30 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 |
The modular metric topology
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11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Sessions: Topology and Order - Topology in Logic and Computer Science Room 2.5 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 |
On the torsion ideal of a homomorphism
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11:30 - 12:00 | |
12:00 - 12:30 |
Homomorphic reverse diferentiation for partial features
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12:30 - 14:15 |
Lunch
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Semi-plenary Talk Room Pedro Nunes (ground floor) | |
14:15 - 15:00 |
What are construction schemes?
Abstract
The method of construction/capturing schemes was introduced by Todorčević. This
technique is a powerful tool that allows us to build uncountable structures with finite
approximations. We will review this method and some applications. This talk will be an introduction and no previous knowledge of the topic is assumed. |
Semi-plenary Talk Room 17 de Abril (ground floor) | |
14:15 - 15:00 |
Quantale-enriched lower separation axioms and the principle of enriched continuous extension
Abstract
Quantale-enriched topological spaces provide a convenient framework to unify constructions from different areas of mathematics such as closed left ideal lattices of non-commutative C∗-algebras, approach spaces, or quantale-valued topological spaces (see [2]). In this talk, we present a quantale-enriched version of the lower separation axioms, with the goal of proving the principle of enriched continuous extension for quantale-enriched topological spaces. This includes a version of the regularity axiom based on the cocompleteness of 𝔔-enriched topologies viewed as 𝔔t-enriched categories and requires the concept of closed 𝔔-enriched presheaves. Moreover, forced by the non-idempotency of the quantale multiplication we also present a completely new and weaker form of regularity, under which the Kolmogoroff, Fréchet and Hausdorff separation axioms are all equivalent. Further, and more importantly, weak regularity is sufficient for the formulation of the principle of continuous extension. As a remarkable result, among other things, we point out that in the case of a commutative Girard quantale 𝔔, every projective 𝔔-module in Sup provided with the interval 𝔔-topology is a Hausdorff and weakly regular 𝔔-enriched topological space. This talk is based on [1] and is joint work with Javier Gutiérrez García (University of the Basque Country UPV/EHU) and Ulrich Höhle (Bergische Universität). References: [1] I. Arrieta, J. Gutiérrez García, and U. Höhle, Enriched lower separation axioms and the principle of enriched continuous extension, Fuzzy Sets and Systems 468, art. no. 108633, 2023. [2] J. Gutiérrez García, U. Höhle, and T. Kubiak, Basic concepts of quantale-enriched topologies, Applied Categorical Structures 29, 983-1003, 2021. |
Session: Set-theoretic Topology Room Pedro Nunes (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
Session: Topological Dynamics and Continuum Theory Room 2.4 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 |
On the dynamics of triangular map and its non-autonomous components
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Session: Topology and Categories - Topology and Order Room 2.5 (2nd floor) | |
15:00 - 15:30 | |
15:30 - 16:00 | |
16:00 - 16:30 | |
16:30 - 17:00 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
17:00 - 17:30 | |
17:30 - 18:00 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
17:00 - 17:30 | |
17:30 - 18:00 | |
19:30 |
Conference Dinner
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Friday, July 12, 2024
Plenary Talk Room Pedro Nunes (ground floor) | |
09:00 - 10:00 |
The appeal of Pointfree Topology (to classical topologists):
These are a few of my favorite things
AbstractIt is over half a century since John Isbell's seminal paper “Atomless Parts of Spaces”
appeared in Mathematica Scandinavica. The last five decades have witnessed a wonderful expansion and understanding of his vision, much of it led by Bernhard Banaschewski.
I will attempt to convince the audience that some of my favourite constructions/ideas
in frame/locale theory may be of use to classical topologists. In particular, I will consider Isbell's density theorem, the Lindelöf (co)reflection (and κ generalizations), the
“cozero” scaffolding and hollowness, and the paracompact (co)reflection of completely
regular frames. If time permits, I will also mention the Bruns-Lakser completion (of a
meet-semilattice). |
10:00 - 10:30 |
Coffee Break
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Session: Set-Theoretical Topology Room Pedro Nunes (ground floor) | |
10:30 - 11:00 |
Fixed points results in M-metric space with applications to LCR circuits
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11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topological Methods in Algebra and Analysis Room 2.4 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 | |
11:30 - 12:00 | |
12:00 - 12:30 | |
Session: Topology and Order Room 2.5 (2nd floor) | |
10:30 - 11:00 | |
11:00 - 11:30 |
Localic properties at infinity
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11:30 - 12:00 | |
12:00 - 12:30 | |
12:30 - 14:15 |
Lunch
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Session: Set-theoretic Topology Room Pedro Nunes (ground floor) | |
14:15 - 14:45 | |
14:45 - 15:15 | |
Session: Topological Dynamics and Continuum Theory Room 17 de Abril (ground floor) | |
14:15 - 14:45 | |
14:45 - 15:15 | |
Session: Topology and Categories Room 2.5 (2nd floor) | |
14:15 - 14:45 |
On effective descent morphisms of lax comma categories of ordered sets
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14:45 - 15:15 | |
Plenary talk Room Pedro Nunes (ground floor) | |
15:15 - 16:15 |
Reconstructing the topology of algebraic structures: how and why
AbstractMany mathematical objects are naturally equipped with both an algebraic and a topological structure. For example, the automorphism group of any first-order structure is,
of course, a group, and in fact a topological group when equipped with the topology of
pointwise convergence. While in some cases, e.g. the additive group of the reals, the algebraic structure of the object alone carries strictly less information than together with the topological structure, in other cases its algebraic structure is so rich that it actually determines the topology (under some requirements on the topology): by a result of Kechris and Solecki, the pointwise convergence topology is the only compatible separable topology on the full symmetric group on a countable set. Which topologies are compatible with a given algebraic object has intrigued mathematicians for decades: for example, Ulam asked whether there exists a compatible locally compact Polish topology on the full symmetric group on a countable set (by the above, the answer is negative). The reconstruction of the topologies of automorphism groups, endomorphism monoids, and polymorphism clones of first-order structures is primarily motivated by model-theoretic questions, but also has applications in theoretical computer science. In the case of automorphism groups, the question of the relationship between the algebraic and the topological structure has been pursued actively over the past 40 years. It turns out that many of the most popular automorphism groups, including that of the order of the rationals and of the random graph, have unique Polish topologies. Endomorphism monoids are algebraically not as rich, and often allow many different compatible topologies. We show, however, that there is a unique compatible Polish topology on the endomorphism monoids of the random graph, the weak linear order of the rational numbers, the random poset, and many more. |
16:15 - 16:30 |
Closing
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16:30 - 17:00 |
Coffee Break
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