Difference between revisions of "Graduate Logic Seminar"
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=== October 28 - Two short talks === | === October 28 - Two short talks === | ||
− | Iván Ongay Valverde and James Earnest Hanson | + | '''Iván Ongay Valverde''' - Exploring different versions of the Semi-Open Coloring Axiom (SOCA) |
+ | |||
+ | In 1985, Avraham, Rubin and Shelah published an article where they introduced different coloring axioms. The weakest of them, the Semi-Open Coloring Axiom (SOCA), states that given an uncountable second countable metric space, $E$, and $W\subseteq E^{\dagger}:=E\times E\setminus \{(x, x) :x \in E\}$ open and symmetric, there is an uncountable subset $H\subseteq E$ such that either $H^{\dagger}\subseteq W$ or $H^{\dagger}\cap W=\emptyset$. We say that $W$ is an open coloring and $H$ is a homogeneous subset of $E$. This statement contradicts CH but, as shown also by Avraham, Rubin and Shelah, it is compatible with the continuum taking any other size. This classic paper leaves some questions open (either in an implicit or an explicit way): | ||
+ | |||
+ | - Is the axiom weaker if we demand that $W$ is clopen? | ||
+ | - If the continuum is bigger than $\aleph_2$, can we ask that $H$ has the same size as $E$? | ||
+ | - Can we expand this axiom to spaces that are not second countable and metric? | ||
+ | |||
+ | These questions lead to different versions of SOCA. In this talk, we will analyze how they relate to the original axiom. | ||
+ | |||
+ | '''James Earnest Hanson''' | ||
+ | |||
+ | TBA | ||
=== November 4 - Two short talks === | === November 4 - Two short talks === |
Revision as of 09:57, 18 October 2019
The Graduate Logic Seminar is an informal space where graduate student and professors present topics related to logic which are not necessarly original or completed work. This is a space focused principally on practicing presentation skills or learning materials that are not usually presented in a class.
- When: Mondays 4p-5p
- Where: Van Vleck B223.
- Organizers: Omer Mermelstein
The talk schedule is arranged at the beginning of each semester. If you would like to participate, please contact one of the organizers.
Sign up for the graduate logic seminar mailing list: join-grad-logic-sem@lists.wisc.edu
Contents
- 1 Fall 2019 - Tentative schedule
- 1.1 September 5 - Organizational meeting
- 1.2 September 9 - No seminar
- 1.3 September 16 - Daniel Belin
- 1.4 September 23 - Daniel Belin
- 1.5 September 30 - Josiah Jacobsen-Grocott
- 1.6 October 7 - Josiah Jacobsen-Grocott
- 1.7 October 14 - Tejas Bhojraj
- 1.8 October 21 - Tejas Bhojraj
- 1.9 October 28 - Two short talks
- 1.10 November 4 - Two short talks
- 1.11 November 11 - Manlio Valenti I
- 1.12 November 18 - Manlio Valenti II
- 1.13 November 25 - Two short talks
- 1.14 December 2 - Iván Ongay Valverde I
- 1.15 December 9 - Iván Ongay Valverde II
- 2 Previous Years
Fall 2019 - Tentative schedule
September 5 - Organizational meeting
September 9 - No seminar
September 16 - Daniel Belin
Title: Lattice Embeddings of the m-Degrees and Second Order Arithmetic
Abstract: Lachlan, in a result later refined and clarified by Odifreddi, proved in 1970 that initial segments of the m-degrees can be embedded as an upper semilattice formed as the limit of finite distributive lattices. This allows us to show that the many-one degrees codes satisfiability in second-order arithmetic, due to a later result of Nerode and Shore. We will take a journey through Lachlan's rather complicated construction which sheds a great deal of light on the order-theoretic properties of many-one reducibility.
September 23 - Daniel Belin
Title: Lattice Embeddings of the m-Degrees and Second Order Arithmetic - Continued
September 30 - Josiah Jacobsen-Grocott
Title: Scott Rank of Computable Models
Abstract: Infinatary logic extends the notions of first order logic by allowing infinite formulas. Scott's Isomorphism Theorem states that any countable structure can be characterized up to isomorphism by a single countable sentence. Closely related to the complexity of this sentence is what is known as the Scott Rank of the structure. In this talk we restrict our attention to computable models and look at an upper bound on the Scott Rank of such structures.
October 7 - Josiah Jacobsen-Grocott
Title: Scott Rank of Computable Codels - Continued
October 14 - Tejas Bhojraj
Title: Solovay and Schnorr randomness for infinite sequences of qubits.
Abstract : We define Solovay and Schnorr randomness in the quantum setting. We then prove quantum versions of the law of large numbers and of the Shannon McMillan Breiman theorem (only for the iid case) for quantum Schnorr randoms.
October 21 - Tejas Bhojraj
Title: Solovay and Schnorr randomness for infinite sequences of qubits.
October 28 - Two short talks
Iván Ongay Valverde - Exploring different versions of the Semi-Open Coloring Axiom (SOCA)
In 1985, Avraham, Rubin and Shelah published an article where they introduced different coloring axioms. The weakest of them, the Semi-Open Coloring Axiom (SOCA), states that given an uncountable second countable metric space, $E$, and $W\subseteq E^{\dagger}:=E\times E\setminus \{(x, x) :x \in E\}$ open and symmetric, there is an uncountable subset $H\subseteq E$ such that either $H^{\dagger}\subseteq W$ or $H^{\dagger}\cap W=\emptyset$. We say that $W$ is an open coloring and $H$ is a homogeneous subset of $E$. This statement contradicts CH but, as shown also by Avraham, Rubin and Shelah, it is compatible with the continuum taking any other size. This classic paper leaves some questions open (either in an implicit or an explicit way):
- Is the axiom weaker if we demand that $W$ is clopen? - If the continuum is bigger than $\aleph_2$, can we ask that $H$ has the same size as $E$? - Can we expand this axiom to spaces that are not second countable and metric?
These questions lead to different versions of SOCA. In this talk, we will analyze how they relate to the original axiom.
James Earnest Hanson
TBA
November 4 - Two short talks
Manlio Valenti and Patrick Nicodemus
November 11 - Manlio Valenti I
November 18 - Manlio Valenti II
November 25 - Two short talks
Speakers TBD
December 2 - Iván Ongay Valverde I
December 9 - Iván Ongay Valverde II
Previous Years
The schedule of talks from past semesters can be found here.