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SUMMARY:Juan Aguilera (Ghent University)
DTSTART;VALUE=DATE-TIME:20211215T163000Z
DTEND;VALUE=DATE-TIME:20211215T173000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/1
DESCRIPTION:Title: The Pi12 Consequences of a Theory\nby Juan Aguile
ra (Ghent University) as part of Bristol Logic and Set Theory Seminar\n\n\
nAbstract\nWe define the \\Pi^1_2-norm |T| of a theory T\, an analogue of
the proof-theoretic ordinal of T for statements of complexity \\Pi^1_2. We
go over the basic theory of |T| and use it to define the \\Pi^1_2-soundne
ss ordinal of T. Then\, we characterise the recursive and admissible ordin
als which are \\Pi^1_2-soundness ordinals of some recursively enumerable e
xtension of Arithmetical Comprehension. This is joint work with Fedor Pakh
omov.\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/1/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Tanmay Inamdar (Bar-Ilan University)
DTSTART;VALUE=DATE-TIME:20220616T140000Z
DTEND;VALUE=DATE-TIME:20220616T153000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/2
DESCRIPTION:Title: From Sierpinski-type colourings to Ulam-type matrices
\nby Tanmay Inamdar (Bar-Ilan University) as part of Bristol Logic and
Set Theory Seminar\n\n\nAbstract\nUlam matrices were introduced by Ulam i
n his study of the measure problem. Ulam's construction applies to all suc
cessor cardinals Kappa\, and later Hajnal extended the construction to app
ly to some limit cardinals as well. In my talk I will show how a colouring
principle introduced by Sierpinski can be used to construct matrices with
similar applications as the matrices of Ulam and Hajnal. I will also show
how such colouring principles can be obtained from the existence of a non
-trivial C-sequence on Kappa using walks on ordinals. As a consequence\, t
he resulting matrices are more readily available than the matrices of Ulam
and Hajnal. The results I present are joint work with Assaf Rinot.\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/2/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Will Stafford (University of Bristol)
DTSTART;VALUE=DATE-TIME:20220929T113000Z
DTEND;VALUE=DATE-TIME:20220929T123000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/3
DESCRIPTION:Title: Is the Proof-Theoretically Valid Logic Intuitionistic
?\nby Will Stafford (University of Bristol) as part of Bristol Logic a
nd Set Theory Seminar\n\n\nAbstract\nSeveral recent results bring into foc
us the superintuitionistic nature of most notions of proof-theoretic valid
ity\, but little work has been done evaluating the consequences of these r
esults. Proof-theoretic validity claims to offer a formal explication of h
ow inferences follow from the definitions of logic connectives (which are
defined by their introduction rules). This paper explores whether the new
results undermine this claim. It is argued that\, while the formal results
are worrying\, superintuitionistic inferences are valid because the treat
ments of atomic formulas are insufficiently general\, and a resolution to
this issue is proposed.\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/3/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Frank Stephan (National University of Singapore)
DTSTART;VALUE=DATE-TIME:20221020T093000Z
DTEND;VALUE=DATE-TIME:20221020T103000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/4
DESCRIPTION:Title: Initial Segment Complexity for Measures\nby Frank
Stephan (National University of Singapore) as part of Bristol Logic and S
et Theory Seminar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/4/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sean Cox (Virginia Commonwealth University)
DTSTART;VALUE=DATE-TIME:20221101T123000Z
DTEND;VALUE=DATE-TIME:20221101T133000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/5
DESCRIPTION:Title: Homological algebra\, elementary submodels\, and stat
ionary logic\nby Sean Cox (Virginia Commonwealth University) as part o
f Bristol Logic and Set Theory Seminar\n\n\nAbstract\nThe talk will focus
on the use of set-theoretic elementary submodel techniques to solve\, or p
artially solve\, some problems from homological algebra (independence of S
alce's Problem about cotorsion pairs\, and the precovering problem in Gore
nstein Homological Algebra).\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/5/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Sam Coskey (Boise State University)
DTSTART;VALUE=DATE-TIME:20221115T123000Z
DTEND;VALUE=DATE-TIME:20221115T133000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/6
DESCRIPTION:Title: Jumps in the Borel complexity hierarchy\nby Sam C
oskey (Boise State University) as part of Bristol Logic and Set Theory Sem
inar\n\nAbstract: TBA\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/6/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Minh Tran (National University of Singapore)
DTSTART;VALUE=DATE-TIME:20230308T163000Z
DTEND;VALUE=DATE-TIME:20230308T173000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/7
DESCRIPTION:Title: Toward classifying the reducts of the complex fields<
/a>\nby Minh Tran (National University of Singapore) as part of Bristol Lo
gic and Set Theory Seminar\n\n\nAbstract\nWe will discuss some recent prog
ress on the problem of classifying the reducts of the complex field (with
named parameters and up to interdefinability). The tools we use include th
e recent solutions of the Restricted Trichotomy Conjecture in characterist
ic 0 and a generalized sumproduct result from additive combinatorics. (Joi
nt with Benjamin Castle)\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/7/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Juan Aguilera (University og Ghent)
DTSTART;VALUE=DATE-TIME:20230322T140000Z
DTEND;VALUE=DATE-TIME:20230322T153000Z
DTSTAMP;VALUE=DATE-TIME:20230331T103433Z
UID:Bristol-logic-and-set-theory/8
DESCRIPTION:Title: A generalization of Borel determinacy\nby Juan Ag
uilera (University og Ghent) as part of Bristol Logic and Set Theory Semin
ar\n\n\nAbstract\nWe present a theorem which is\, in some sense\, the prov
ably optimal generalization of Martin's Borel determinacy for infinite gam
es on integers. \n\nPlease see below or the seminar webpage https://www.br
istolmathsresearch.org/seminar/juan-aguilera-3 for the zoom link.\n
LOCATION:https://researchseminars.org/talk/Bristol-logic-and-set-theory/8/
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