To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Following Karl Rubin’s lecture last week we will consider the “relative Diophantine notion”: a field extension L/K is Diophantine Stable for a variety V defined over K if V acquires no new rational points passing from K to L. I will discuss results, heuristics, conjectures related to Diophantine Stability, and especially: applications to Hilbert’s Tenth Problem. This consists of both joint work with Karl Rubin; and also a DDC workshop project with Karl Rubin and Sasha Shlapentokh.

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

Tea for members and participants of the Random and Arithmetic Structures in Topology program.

To participate, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Abstract:
So you teach a decent class.  Great.  Everybody does.  You prove a good theorem.  Everybody proves a good theorem.  What else have you got?  The market usually contains many jobs that focus on a small pool of candidates who have a specialized skill, and even in other positions, it is better to be memorable as “the one who…”  We’ll talk about some ways that people distinguish themselves and how to find and develop your own superpowers.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Abstract:

Starting from the model theory of tame fields developed in
    Kuhlmann, F.-V.: The algebra and model theory of tame valued fields, J. reine angew. Math. 719 (2016), 1-43,
one main question is how the condition of tameness can be relaxed while preserving some structure theory that still could lead to good model theoretic results. A first step was made in
    Kuhlmann, F.-V. - Pal, K.: The model theory of separably tame fields, J. Alg. 447 (2016), 74-108,
but these fields are still very close to tame fields. My approach to the question is to use a classification of the defects of valued field extensions. One of the two types types of defect has been identified as the more harmful, so the question arises: which classes of valued fields avoid the harmful defects? It turns out that a slight generalization of the deeply ramified fields does the job. We will introduce this class of valued fields as well as the deeply ramified fields and the so-called semitame fields.
To cover all deeply ramified fields, it was crucial to generalize the classification of defects that was originally given only in the equal characteristic case to the mixed characteristic case. In a new development, this can now be done by a unified definition that does not need a case distinction, by identifying an interesting invariant of defect extensions of prime characteristic.
In my talk I will also describe a challenging open problem: prove by purely valuation theoretical means the known fact that algebraic extensions of deeply ramified fields are again deeply ramified.
All this contains no model theoretic results so far (in contrast to the theory of tame and separably tame fields). The aim is to build a structure theory that then, hopefully, can be used by model theorists to push beyond tame fields. I will mention in passing a relatively new result that indirectly is connected with model theory: valued fields with only finitely Artin-Schreier extensions (as are the NTP2 valued fields) are deeply ramified (and even semitame).

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Abstract:

For many (but not all) properties, a reduct of a structure M is no more complicated than M itself.  For example, if M is decidable, so are each of its reducts (in a reasonable language).  However, Borel completeness, which is a measure of ‘maximal complexity’ is not like this.  We recently showed that if M has uncountably many 1-types (with respect to its theory) then M has a Borel complete reduct.  No background is assumed -- at least the first half of the talk will be spent on defining reducts and Borel completeness, and giving algebraic examples.   This is joint work with Douglas Ulrich.

To attend this seminar, please register here: https://www.msri.org/seminars/25205

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, you must register in advance, by clicking HERE.

One consequence of the recent push to develop a scheme theory in tropical geometry has been the development of a tropical commutative algebra. This starts with the commutative algebra of semirings, but in order to get a theory that interacts with geometry, we are lead to impose some combinatorial, matroid-theoretic, conditions. I will introduce these ideas, and discuss the current state of our understanding.

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

Abstract:

We define notions of generically and coarsely computable and computably enumerable structures.  There are two directions in which these notions could potentially trivialize: either all structures could have a densely computable copy or only those having a computable (or computably enumerable) copy.  We show that particular classes of structures realize each of these extremal conditions, while other classes realize neither of them.

To further explore these concepts, we introduce a graded family of elementarity conditions for substructures, in which we require that the dense sets under consideration be a strong substructure of the original structure.  Here, again, for a given class the notion could trivialize in the same two directions, and we show that both are possible.  For each class we investigate, there is some n such that requiring Sigma_n-elementarity is enough to minimize the class of generically or densely computable structures, witnessing the essentially structural character of these notions.

To attend this seminar, please register here: https://www.msri.org/seminars/25205

Tea for members and participants of the Decidability, definability and computability in number theory virtual program.

To participate, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, you must register in advance, by clicking HERE.

Let A -> B be a flat local map of noetherian complete local rings. Using Hironaka's resolution of singularities, Grothendieck and Dieudonné showed that if the closed fiber of the map A -> B is Cohen-Macaulay and if A is of equal characteristic zero, then all the fibers of A -> B are Cohen-Macaulay. Three decades later, Avramov and Foxby showed that the same statement holds without the characteristic assumption on A. Grothendieck's localization problem asks whether a similar statement holds with Cohen-Macaulayness replaced by other local properties of noetherian local rings. We solve Grothendieck's localization problem for all sufficiently well-behaved properties of noetherian local rings. Our proof provides a uniform treatment of previously known special cases of Grothendieck's problem, in particular giving a new proof of Avramov and Foxby's result. As an application, we show that if the closed fibers of a flat morphism of algebraic varieties are smooth, then all fibers are smooth.

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

To attend this seminar, please register here: https://www.msri.org/seminars/25205

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To attend this seminar, you must register in advance, by clicking HERE.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25205

This is one of the research seminars for the RAS program, that distinguishes itself from the postdocs and program associates seminars in that speakers are chosen among Research Members, Research Professors with occasional outside speakers.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate, please email Tommaso Cremaschi or James Farre.

Valuation theory plays a major part in the interaction between number theory and logic. In this seminar, a variety of topics from valuation theory, and in particular connections to model theory, will be discussed. There will be a strong emphasis on results involving the definability of valuations.

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To participate in this seminar, please register here: https://www.msri.org/seminars/25206

To attend this seminar, please register here: https://www.msri.org/seminars/25205

To participate in this seminar, please register here: https://www.msri.org/seminars/25206