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SUMMARY:Jason Parker (Brandon)
DTSTART:20210430T150000Z
DTEND:20210430T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/1
DESCRIPTION:Title: Isotropy Groups of Quasi-Equational Theories\nby Jason Parker
(Brandon) as part of Logic Supergroup\n\n\nAbstract\nIn [2]\, my PhD super
visors (Pieter Hofstra and Philip Scott) and I studied the new topos-theor
etic phenomenon of isotropy (as introduced in [1]) in the context of singl
e-sorted algebraic theories\, and we gave a logical/syntactic characteriza
tion of the\nisotropy group of any such theory\, thereby showing that it e
ncodes a notion of inner automorphism or conjugation for the theory. In th
e present talk\, I will summarize the results of my recent PhD thesis\, in
which I build on this earlier work by studying the isotropy groups of (mu
lti-sorted) quasi-equational theories (also known as essentially algebraic
\, cartesian\, or finite limit theories). In particular\, I will show how
to give a logical/syntactic characterization of the isotropy group of any
such theory\, and that it encodes a notion of inner automorphism or conjug
ation for the theory. I will also describe how I have used this characteri
zation to exactly characterize the ‘inner automorphisms’ for several d
ifferent examples of quasi-equational theories\, most notably the theory o
f strict monoidal categories and the theory of presheaves valued in a cate
gory of models. In particular\, the latter example provides a characteriza
tion of the (covariant) isotropy group of a category of set-valued preshea
ves\, which had been an open question in the theory of categorical isotrop
y. \n\n[1] J. Funk\, P. Hofstra\, B. Steinberg. Isotropy and crossed topos
es. Theory and Applications of Categories 26\, 660-709\, 2012.\n\n[2] P. H
ofstra\, J. Parker\, P.J. Scott. Isotropy of algebraic theories. Electroni
c Notes in Theoretical Computer Science 341\, 201-217\, 2018.\n\nhttps://s
ites.google.com/view/logicsupergroup/\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/1/
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BEGIN:VEVENT
SUMMARY:Romina Padro (CUNY)
DTSTART:20210507T150000Z
DTEND:20210507T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/2
DESCRIPTION:by Romina Padro (CUNY) as part of Logic Supergroup\n\nAbstract
: TBA\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Francesca Boccuni & Luca Zanetti (Vita-Salute San Raffaele & IUSS
Pavia)
DTSTART:20210514T150000Z
DTEND:20210514T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/3
DESCRIPTION:Title: How to Hamlet a Caesar\nby Francesca Boccuni & Luca Zanetti (V
ita-Salute San Raffaele & IUSS Pavia) as part of Logic Supergroup\n\n\nAbs
tract\nNeologicism aims at providing a foundation for arithmetic on the ba
sis of so-called Hume's Principle (HP)\, which states that the number of t
he Fs is identical with the number of the Gs iff there is one-to-one corre
spondence between the concepts F and G. Philosophically\, Neologicism amou
nts to three main claims: (1) HP is analytic\; (2) HP is \;a priori
\; (3) HP captures the nature of cardinal numbers. Nevertheless\, Neol
ogicism is faced with the so-called \;Caesar problem: though HP
provides an implicit definition of the concept \;Cardinal Number\, which arguably might be known a priori\, HP does not determine the tr
uth-value of mixed identity statements such as "Caesar=4". Neologicists ta
ckle the Caesar problem by claiming that the applicability conditions of t
he concept \;Cardinal Number \;can be obtained from the ide
ntity conditions determined by HP\, so that the truth of mixed identity st
atements as "Caesar=4" can be determined in the negative. In this talk\, w
e will argue that the Neologicist solution to the Caesar problem gives ris
e to what we call the \;Caesar Problem problem: if the Caesar p
roblem is indeed solved as Neologicists claim\, then (1)-(3) cannot be joi
ntly argued for. \;We will consider some ways in which Neologicists ca
n try to solve the Caesar Problem problem\, and we will argue that none of
these solutions are favourable to them. Finally\, we will investigate the
consequences of the Caesar Problem problem for Neologicism. \;\n\
nhttps://sites.google.com/view/logicsupergroup/\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/3/
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BEGIN:VEVENT
SUMMARY:John Baldwin (UIC)
DTSTART:20210521T150000Z
DTEND:20210521T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/4
DESCRIPTION:by John Baldwin (UIC) as part of Logic Supergroup\n\nAbstract:
TBA\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bruno Da Re (Conicet/UBA)
DTSTART:20210528T150000Z
DTEND:20210528T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/5
DESCRIPTION:by Bruno Da Re (Conicet/UBA) as part of Logic Supergroup\n\nAb
stract: TBA\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cristóbal Rojas (Andrés Bello)
DTSTART:20210611T150000Z
DTEND:20210611T170000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/6
DESCRIPTION:by Cristóbal Rojas (Andrés Bello) as part of Logic Supergrou
p\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Verónica Becher (Universidad de Buenos Aires)
DTSTART:20210618T010000Z
DTEND:20210618T030000Z
DTSTAMP:20260422T225659Z
UID:LogicSupergroup/7
DESCRIPTION:Title: Random!\nby Verónica Becher (Universidad de Buenos Aires) as
part of Logic Supergroup\n\n\nAbstract\nEveryone has an intuitive idea abo
ut what randomness is\, often associated with "gambling" or "luck". Is the
re a mathematical definition of randomness? Are there degrees of randomnes
s? Can we give examples of randomness? Can a computer produce a sequence t
hat is truly random? What is the relation between randomness\, logic\, lan
guage and information? I will talk about these questions and their answers
.\n
LOCATION:https://researchseminars.org/talk/LogicSupergroup/7/
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