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Conference on Theoretical and Computational Algebra 2025
Conference on Theoretical and Computational Algebra 2025
29 June 2025 - 4 July 2025 -
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Conference on Theoretical and Computational Algebra 2025
Conference on Theoretical and Computational Algebra 2025
29 June 2025 - 4 July 2025 -
More information is available here.
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3
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Conference on Theoretical and Computational Algebra 2025
Conference on Theoretical and Computational Algebra 2025
29 June 2025 - 4 July 2025 -
More information is available here.
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4
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Conference on Theoretical and Computational Algebra 2025
Conference on Theoretical and Computational Algebra 2025
29 June 2025 - 4 July 2025 -
More information is available here.
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[SAn] Nonlinear dynamics and bifurcations in epidemic models | Prof. JoĂŁo Carvalho (Centre for Mathematics, University of Porto & Prince Henry Portucalense University)
[SAn] Nonlinear dynamics and bifurcations in epidemic models | Prof. JoĂŁo Carvalho (Centre for Mathematics, University of Porto & Prince Henry Portucalense University)
4 July 2025 - 2:15 pm - 3:15 pm
Room 4.7, Building VIII
Seminar of Analysis
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Speaker:Â Prof. JoĂŁo Carvalho (Centre for Mathematics, University of Porto &Prince Henry Portucalense University).
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Date/time:Â 04/07/2025 (Friday), from 14:15 to 15:15.
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Location:Â Room 4.7, Building VIII.
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Title: Nonlinear dynamics and bifurcationsin epidemic models
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Abstract: Â In thefirst part we analyze a periodically forced SIR model. We prove that for $R0< 1$ the system exhibits multiple endemic equilibria -- backwardbifurcation. Using the theory of strange attractors, we prove the persistenceof strange attractors for an open subset in the parameter space where R0 < 1.
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In the second part, we address a modified SIRmodel with a constant vaccination strategy and the bifurcations it unfolds. Weexplicitly prove that the endemic equilibrium is a codimension two singularityin the parameter space (R0, p), where R0 is the basic reproduction number and pis the proportion of susceptible individuals successfully vaccinated at birth.The analytical expressions of the bifurcation curves as a function of R0 and pestimate the proportion of vaccinated susceptible individuals necessary for thedisease to be eliminated from the population.
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In the third part we present our ongoing work.We focus on two main topics: (i) in the absence of seasonality, the endemic(and unique) equilibrium point undergoes supercritical and subcritical Hopfbifurcations; (ii) in the presence of seasonality, we conjecture that, via thetorus breakdown theory, the system exhibits chaotic dynamics.
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In the fourth and final part, we present arecent model describing the coinfection dynamics of HIV and SARS-CoV-2 underhighly active antiretroviral therapy (HAART). Unlike previous models, ourformulation incorporates the effect of HAART on both infections. We derive thebasic reproduction numbers for each virus and show that transcriticalbifurcations occur when these values cross the threshold of one. We alsoestablish stability conditions for the disease-free equilibria. Numericalsimulations reveal that HAART, although targeting HIV, may also reduceSARS-CoV-2 proliferation in coinfected individuals -- suggesting a potentialindirect benefit not widely addressed in the existing literature.
This is joint work with Professor Alexandre Rodrigues (ISEG).
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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7
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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[SAL] Congruence Lattices of Finite Twisted Brauer and Temperley-Lieb Monoids | Matthias Fresacher (Western Sydney University)
[SAL] Congruence Lattices of Finite Twisted Brauer and Temperley-Lieb Monoids | Matthias Fresacher (Western Sydney University)
7 July 2025 - 2:00 pm - 3:00 pm
Room 1, Building XI
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Abstract:
In 2022, East and RuĆĄkuc published the congruence lattice of the infinite twisted partition monoid. As a by product, they established the congruence lattices of the finite $d$-twisted partition monoids. This talk is a first step in adapting the work of East and RuĆĄkuc to the setting of the Brauer and Temperley-Lieb monoid. Specifically, it presents the newly established congruence lattice of the $0$-twisted Brauer and Temperley-Lieb monoids. With simple to grasp visual multiplication and applications in theoretical physics and representation theory, the family of diagram monoids are of particular interest to a number of fields as well are of stand alone interest.
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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10
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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[SSRM & MatHBioS] Remodelling Selection to overcome Selective Depletion Biases | Gabriela Gomes, University of Strathclyde (UK) and NOVA Math
[SSRM & MatHBioS] Remodelling Selection to overcome Selective Depletion Biases | Gabriela Gomes, University of Strathclyde (UK) and NOVA Math
10 July 2025 - 2:30 pm - 3:30 pm
Statistics and Risk Management Seminar & Thematic Line MatHBioS (Mathematics for Health and BioSciences)
Department of Mathematics, NOVA MATH/FCT NOVA
Title:Â Remodelling Selection to overcome Selective Depletion Biases
Speaker: Gabriela Gomes, University of Strathclyde and NOVA Math
Date | Time:Â July 10, 2025Â | 14:30
Location:Â VIII-3.4
Abstract: Every population consists of individuals that vary in many traits, and each trait may or may not be associated with fitness. Variation in fitness traits lends population studies prone to selective depletion biases. When an ageing cohort exhibits declining mortality, it could be individuals becoming healthier or selective depletion of the frail. In an epidemic, when growth in cumulative infections decelerates, it could be individuals cautiously changing behaviour or selective depletion of the most susceptible. In microbial populations, when an isogenic population is stressed by antimicrobial treatment and some cells survive, this could be due to individual cells switching between normal and persister phenotypes or antibiotic selectively killing cells that divide faster. In each case, the first explanation invokes individuals changing (1), while the second posits selection on pre-existing variation changing (2). While explanations of type (1) are intuitive and widely adopted, those of type (2) are more neutral and rarely considered due to cognitive biases and challenges in estimating all variation that matters. While both are plausibly operating in most real systems, neglect of (2) leads to over-attribution of results to (1), wrong predictions, bad policy decisions and poor reproducibility, negatively impacting science, economics and ethics. To overcome this selective depletion bias, I have been proposing a pragmatic approach to study design and analysis whereby we infer distributions of characteristics that respond to selection and reframe theories accordingly. The approach is based on remodelling selection (mathematically by introducing key parametric distributions into population dynamic models, and empirically by measuring quantities of interest along selection gradients) and statistical inference (by fitting mathematical models to data). The procedure is being tested in systems where trait distributions can be inferred from population trends as well as reconstructed directly from individual measurements. Results of this ongoing research will be presented, and the wider applicability discussed. Prospects for conducting some of this research at NOVA School of Science and Technology are being assessed. Please join the discussion if you find the topic interestingâŠ
Short Bio: Gabriela Gomes graduated in Applied Mathematics from the University of Porto in 1987 and completed her MSc and PhD in Mathematics from the University of Warwick in 1990 and 1993, respectively. In 1999, she switched to biology with a Wellcome Research Training Fellowship in Mathematical Biology. In 2002, she established an independent research group at the Gulbenkian Science Institute (IGC), initially supported by a Marie Curie Excellence Grant, with a spectrum of projects ranging from fundamental mathematical concepts to the management of population and ecosystem health, public engagement in science and development of research infrastructures. She subsequently led research programmes in the Research Centre for Biodiversity and Genetic Resources (CIBIO-InBIO), the Liverpool School of Tropical Medicine (LSTM), and is now a Professor of Mathematics and Statistics at the University of Strathclyde. Gabriela in a member of NOVA Math since 2023 where she leads the participation of the centre in the European project Inno4Vac (Innovations to accelerate vaccine development and manufacture).
Gabriela Gomes has published around 100 peer-reviewed research papers in international journals, initially in Mathematics and Physics and later in Biology, Ecology and Epidemiology. She has been a member of Editorial Boards for Nature Scientific Reports, Journal of Mathematical Biology and Journal of Theoretical Biology, and integrated the Board of Directors of the Portuguese Mathematical Society twice. She held various visiting positions in the USA and Brazil and is a Fellow of the Institute of Mathematics and its Applications (FIMA) in the UK.
Organizers:Â Isabel NatĂĄrio and Paula PatrĂcio
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This work is funded by national funds through the FCT â Fundação para a CiĂȘncia e a Tecnologia, I.P., under the scope of the projects UIDB/00297/2020 (https://doi.org/10.54499/UIDB/00297/2020) and UIDP/00297/2020 (https://doi.org/10.54499/UIDP/00297/2020) (Center for Mathematics and Applications)
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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12
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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13
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[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
[VAL] Charles Johnson (The College of William & Mary, Williamsburg, Virginia, USA)
5 July 2025 - 13 July 2025 -
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Computability in Europe (CiE) 2025
Computability in Europe (CiE) 2025
14 July 2025 - 18 July 2025 -
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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Computability in Europe (CiE) 2025
Computability in Europe (CiE) 2025
14 July 2025 - 18 July 2025 -
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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Computability in Europe (CiE) 2025
Computability in Europe (CiE) 2025
14 July 2025 - 18 July 2025 -
More information is available here.
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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Computability in Europe (CiE) 2025
Computability in Europe (CiE) 2025
14 July 2025 - 18 July 2025 -
More information is available here.
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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18
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Computability in Europe (CiE) 2025
Computability in Europe (CiE) 2025
14 July 2025 - 18 July 2025 -
More information is available here.
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
[VSRM] Kamila TrzciĆska (Department of Statistical Methods, Faculty of Economics and Sociology University of Lodz, Poland)
14 July 2025 - 22 July 2025 -
Venue: office 410, 4th floor of the "Departamento de Engenharia MecĂąnica e Industrial (DEMI)" Building
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