# Calendar

Oct
20
Tue
Break (University of Hawaiʻi) @ Lecture held in Elysium
Oct 20 @ 6:00 am – 8:00 am

Title: Topological Groups Seminar Two-Week Hiatus
by Break (University of Hawaiʻi) as part of Topological Groups

Lecture held in Elysium.
Abstract: TBA

Oct
27
Tue
Wayne Lewis (University of Hawaiʻi) @ Lecture held in Elysium
Oct 27 @ 6:00 am – 8:00 am

Title: Abelian Varieties as Algebraic Protori?
by Wayne Lewis (University of Hawaiʻi) as part of Topological Groups

Lecture held in Elysium.

Abstract
An outcome of the structure theory of protori (compact connected abelian groups) is their representability as quotients of $mathbb{A}^n$ for the ring of adeles $mathbb{A}$. $mathbb{A}$ does not contain zeros of rational polynomials, but rather representations of zeros. Investigating the relations between algebraicity of complex tori and algebraicity of protori leads one to the problem of computing the Pontryagin dual of $mathbb{A}/mathbb{Z}$. Applying an approach by Lenstra in the setting of profinite integers to the more general $mathbb{A}$ leads to a definition of the closed maximal $Lenstra$ $ideal$ $E$ of $mathbb{A}$, whence the locally compact field of $adelic$ $numbers$ $mathbb{F}=mathbb{A}/E$, providing a long-sought connection to $mathbb{C}$ enabling one to define a functor from the category of complex tori to the category of protori – is it possible to do so in a way that preserves algebraicity? While $mathbb{F}$ marks tentative progress, much work remains…

Nov
3
Tue
Wayne Lewis (University of Hawaiʻi) @ Lecture held in Elysium
Nov 3 @ 6:00 am – 8:00 am

Title: Accounting with $mathbb{QP}^infty$
by Wayne Lewis (University of Hawaiʻi) as part of Topological Groups

Lecture held in Elysium.

Abstract
Rational projective space provides a useful accounting tool in engineering decompositions of $mathbb{Q}[x]$ for desired effect. The device is useful for defining a correspondence between summands of such a decomposition and elements of a partition of $mathbb{A}$. This mechanism is applied to a decomposition of $mathbb{Q}[x]$ relative to which the correspondence gives the $Lenstra$ $ideal$ $E$, a closed maximal ideal yielding the $adelic$ $numbers$ $mathbb{F}=frac{mathbb{A}}{E}$.

Nov
10
Tue
Monique Chyba (University of Hawaiʻi) @ Lecture held in Elysium
Nov 10 @ 6:00 am – 8:00 am

Title: Journey in Hawaii’s Challenges in the Fight Against COVID-19
by Monique Chyba (University of Hawaiʻi) as part of Topological Groups

Lecture held in Elysium.

Abstract
The COVID-19 pandemic is far from the first infectious disease that Hawaiʻi had to deal with. During the 1918-1920 Influenza Pandemic, the Hawaiian islands were not spared as the disease ravaged through the whole world. Hawaiʻi and similar island populations can follow a different course of pandemic spread than large cities/states/nations and are often neglected in major studies. It may be too early to compare the 1918-1920 Influenza Pandemic and COVID-19 Pandemic, we do however note some similarities and differences between the two pandemics.

Hawaiʻi and other US Islands have recently been noted by the media as COVID-19 hotspots after a relatively calm period of low case rates. U.S. Surgeon General Jerome Adams came in person on August 25 to Oahu to address the alarming situation. We will discuss the peculiarity of the situation in Hawaiʻi and provide detailed modeling of current virus spread patterns aligned with dates of lockdown and similar measures. We will present a detailed epidemiological model of the spread of COVID-19 in Hawaiʻi and explore effects of different intervention strategies in both a prospective and retrospective fashion. Our simulations demonstrate that to control the spread of COVID-19 both actions by the State in terms of testing, contact tracing and quarantine facilities as well as individual actions by the population in terms of behavioral compliance to wearing a mask and gathering in groups are vital. They also explain the turn for the worst Oahu took after a very successful stay-at-home order back in March.

Nov
24
Tue
Seid Kassaw (University of Cape Town) @ Lecture held in Elysium
Nov 24 @ 6:00 am – 8:00 am

Title: The probability of commuting subgroups in arbitrary lattices of subgroups
by Seid Kassaw (University of Cape Town) as part of Topological Groups

Lecture held in Elysium.

Abstract
The subgroup commutativity degree $sd(G)$ of a finite group $G$ was introduced
almost ten years ago and deals with the number of commuting subgroups in the
subgroup lattice $L(G)$ of $G$. The extremal case $sd(G) = 1$ detects a class of groups
classified by Iwasawa in 1941 (in fact, $sd(G)$ represents a probabilistic measure which
allows us to understand how far $G$ is from the groups of Iwasawa). This means
$sd(G) = 1$ if and only if $G$ is the direct product of its Sylow $p$-subgroups and these
are all modular; or equivalently $G$ is a nilpotent modular group. Therefore, $sd(G)$ is
strongly related to structural properties of $L(G)$ and $G$.

In this talk, we introduce a new notion of probability $gsd(G)$ in which two arbitrary sublattices $S(G)$ and $T(G)$ of $L(G)$ are involved simultaneously. In case
$S(G) = T(G) = L(G)$, we find exactly $sd(G)$. Upper and lower bounds for $gsd(G)$
are shown and we study the behaviour of $gsd(G)$ with respect to subgroups and
quotients, showing new numerical restrictions. We present the commutativity
and subgroup commutativity degree for infinite groups and put some open problems
for further generalization.

Dec
1
Tue
Farzana Nasrin (University of Hawaiʻi) @ Lecture held in Elysium
Dec 1 @ 6:00 am – 8:00 am

Title: Bayesian Statistics, Topology and Machine Learning for Complex Data Analysis
by Farzana Nasrin (University of Hawaiʻi) as part of Topological Groups

Lecture held in Elysium.

Abstract
Analyzing and classifying large and complex datasets are generally challenging. Topological data analysis, that builds on techniques from topology, is a natural fit for this. Persistence diagram is a powerful tool that originated in topological data analysis that allows retrieval of important topological and geometrical features latent in a dataset. Data analysis and classification involving persistence diagrams have been applied in numerous applications. In this talk, I will provide a brief introduction of topological data analysis, focusing primarily on persistence diagrams, and a Bayesian framework for inference with persistence diagrams. The goal is to provide a supervised machine learning algorithm in the space of persistence diagrams. This framework is applicable to a wide variety of datasets. I will present applications in materials science, biology, and neuroscience.

Dec
8
Tue
Mikhail Tkachenko (Metropolitan Autonomous University) @ Lecture held in Elysium
Dec 8 @ 6:00 am – 8:00 am

Title: Pseudocompact Paratopological and Quasitopological Groups
by Mikhail Tkachenko (Metropolitan Autonomous University) as part of Topological Groups

Lecture held in Elysium.

Abstract
Pseudocompactness is an interesting topological property which acquires very specific
features when applied to different algebrotopological objects. A celebrated theorem
of Comfort and Ross published in 1966 states that the Cartesian product of an arbitrary
family of pseudocompact topological groups is pseudocompact. We present a survey
of results related to the validity or failure of the Comfort-Ross’ theorem in the realm of
semitopological and paratopological groups and give some examples showing that
pseudocompactness fails to be stable when taking products of quasitopological groups.