Department of Mathematics

Mathematics 253-37 | Caltech
1200 E California Blvd | Pasadena, CA 91125
Tel: (626) 395-4335 | Fax: (626) 585-1728

Logic in Southern California

Saturday, November 17, 2012
2:00 - 6:00 pm
Sloan room 151

Funded by NSF grant DMS-1044150


2:00-3:00 Aleksandra Kwiatkowska (UCLA)
3:15-4:15 Miodrag Sokic (Caltech)
4:15-5:00 Coffee Break
5:00-6:00 Andrew Marks (Caltech)

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Aleksandra Kwiatkowska (UCLA). Speaker information

Title:Comeager conjugacy classes in automorphism groups and the pseudo-arc
Abstract: The pseudo-arc is an important example of a hereditary indecomposable compact and connected space. As proved by Irwin and Solecki, the pseudo-arc can be realized as a natural quotient of a certain projective Fraisse limit L. We show that the group of all automorphisms of L, Aut(L), has a comeager conjugacy class. This generalizes a very recent result due to Oppenheim, who showed that Aut(L) has a dense conjugacy class.

Miodrag Sokic (Caltech). Speaker information

Title: A generalization of the Partite Construction
Abstract: The Ramsey property for ordered graphs was proved independently by Nesetril-Rodl and Abramson-Harrington. The main ingredient of the Nesetril-Rodl proof is the so-called partite lemma, which shows that only specific objects, called transversals, have the Ramsey property. We give a generalization of this lemma by replacing transversal objects by arbitrary objects in the corresponding class of finite relational structures. In particular we consider relational classes obtained by adding unary relations or equivalence relations to structures. We obtain not only combinatorial results but we also give a topological interpretation of our results. We calculate the universal minimal flow for certain groups of automorphisms of countable structures.

Andrew Marks (Caltech). Speaker information

Title: Borel combinatorics and the Borel cardinality of recursive isomorphism
Abstract: We use determinacy to settle several questions in Borel combinatorics related to colorings and matchings of n-regular graphs. We then describe how these results can be used to show that recursive isomorphism on 2ω is not a universal countable Borel equivalence relation in a "nicely uniform" way.

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Directions and Parking:


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1200 E. California Blvd.
Pasadena, CA 91125

Take a look at the Caltech campus map.

There is free Saturday parking in underground structure #126. Feel free to park in any of the commuter spaces (these are marked by a red line).

Talks will be held in Sloan building #37, Room 159 on the ground floor

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Alexander Kechris (Caltech). Organizer Information
Itay Neeman (UCLA). Organizer Information
Martin Zeman (UCI) Organizer Information

Local Organizers:

Alexander Kechris (Caltech)
Robin Tucker-Drob (Caltech) Local Organizer Information

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Past Meetings:

May 12, 2012 - at UCLA

February 18, 2012 - at Caltech

December 3, 2011 - at UC Irvine

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