Data for paper "Different cadaver astigmatan mites (Arthropoda: Acari) are designed to bite flesh differently" by C E Bowman in The Science of Nature
Bowman, C
(01 Jan 2026)
Thu, 23 Apr 2026
17:00
17:00
L4
Conjugacy of trivial autohomeomorphisms of $\beta N\setminus N$.
Ilijas Farah
(York University, Toronto)
Abstract
An autohomeomorphism of the Čech--Stone remainder $\beta N\setminus N$ is called trivial if it has a continuous extension to a map from $\beta N$ into itself. Such map is determined by an almost permutation, which is a bijection between cofinite subsets of $N$. By results of W. Rudin and S. Shelah, the question whether nontrivial autohomeomorphisms of $\beta N\setminus N$ exist is independent from ZFC. We will be considering the so-called rotary autohomeomorphisms. An autohomeomorphism is called rotary if it corresponds to a permutation of $N$ all of whose cycles are finite. If all autohomeomorphisms are trivial, then the problem of their conjugacy is also trivial (in the usual sense of the word). However the Continuum Hypothesis makes the conjugacy relation nontrivial. While our results are somewhat incomplete, they suffice to decide whether for example the rotary autohomeomorphisms whose cycles have lengths $2^{2n}$, for $n\in N$, and $2^{2n+1}$, for $n\in N$, are conjugate. This is a joint work with Will Brian.
Tue, 16 Jun 2026
14:00 -
15:00
L6
The question of profinite isomorphism
Dan Segal
(Oxford)
Abstract
The question is this: can one effectively decide whether two given groups have isomorphic profinite completions? Thanks to Bridson and Wilton, it is known that the answer is `no' in general, even for finitely presented residually finite groups. However, if the groups are (and are given to be) virtually polycyclic, then the answer is 'yes'. This is not really surprising, as a lot is known both about the profinite completions of such groups and about how they are determined up to isomorphism; but it may be instructive to see how it is done.
Numerical studies of the power-sharing during MAST L-mode discharges
Xia, Q
Militello, F
Moulton, D
Omotani, J
Nuclear Fusion
volume 66
issue 4
046034-046034
(01 Apr 2026)
Preface
Fowler, A
Ng, F
Springer Textbooks in Earth Sciences Geography and Environment
volume Part F10283
xi-xiii
(01 Jan 2021)
Robustness Verification of Graph Neural Networks Via Lightweight Satisfiability Testing
Lu, C
Tan, T
Benedikt, M
Tools and Algorithms for the Construction and Analysis of Systems
volume 16505
3-22
(16 Apr 2026)
Thu, 11 Jun 2026
17:00
17:00
L3
Aspects of 2-categorical logic
Nicola Gambino
(Manchester University)
Abstract
Two ideas underpin categorical logic: first, that a theory can be identified with its associated syntactic category; secondly, that the set-theoretic models of a theory can be identified with functors from its syntactic category to the category of sets and functions preserving suitable structure. This point of view is useful because it often helps us to establish existence of free models. After reviewing these ideas, I will present joint work with Giacomo Tendas on variant in the context of 2-dimensional category theory, in which we are interested in categories, rather than sets, equipped with additional structure (often subject to universal properties). Extra subtleties emerge, as one needs to deal with a form of quantification in between `there exists’ and `there exists a unique’. As an application, we obtain a variety of free 2-categorical constructions, including Joyal’s free bicompletions.
Thu, 14 May 2026
17:00
17:00
L3
Is Fp((Q)) NTP2?
Blaise Boissonneau
(HHU Düsseldorf)
Abstract
7 years ago, also in Oxford, Sylvy Anscombe and I asked this question, which is part of the general effort to try and understand the model theory of henselian valued fields through dividing lines. In 2024, Sylvy Anscombe and Franziska Jahnke completely classified NIP henselian valued fields. Their methods can be extended, with the help of works of Chernikov, Kaplan and Simon and of Kuhlmann and Rzepka, to NTP2 henselian valued fields, obtaining the following:
- if a henselian valued field is NTP2, then it is semitame and its residue field is NTP2;
- if a henselian valued field is separably algebraically maximal Kaplansky and its residue field is NTP2, then it is NTP2.
This covers a large class of fields, but there is still a gap. Notably, Fp((Q)) is in the middle: it is semitame but not Kaplansky.
To answer this question, we studied so called tame henselian fields with finite residue field, and derived quantifier elimination results, namely, we prove that any formula in the language of valued fields reduces to a formula of the form (∃y f(x,y)=0) ∧ φ(v(x)) ∧ ψ(res(x)), where φ and ψ are formulas in the language of ordered groups and of rings, respectively.
In Fp((Q)) specifically, the valuation ring itself is definable with a diophantine formula (ie of the form ∃y f(x,y)=0), reducing further our quantifier elimination result.
Finally, a large chunk of these formulas are known to be NTP2: when f(x,y) is additive in y, the formula ∃y f(x,y)=z is NTP2 (with respect to x and z). Unfortunately, that does not cover all formulas, so the answer to the titular question is still unknown.
Thu, 07 May 2026
17:00
17:00
L3
Definable henselian valuations, revisited
Franziska Jahnke
(Universitat Munster)
Abstract
Non-trivial henselian valuations are often so closely related to the
arithmetic of the underlying field that they are encoded in it, i.e., that
their valuation ring is first-order definable in the language of rings. In
this talk, I will survey and present old and new results around the
definability of henselian valuations, also with a view towards parameters and
uniformity of definitions.