Search
Recent seminar announcements
 Damian Sobota: JosefsonNissenzweig theorem for $C(K)$spaces Wrocław University of Technology
 Saeed Ghasemi: AFalgebras with Cantorset property Prague Set Theory Seminar
 Ashutosh Kumar: Order dimension of Turing degrees NUS logic seminar
 Spencer Unger: Stationary reflection and the singular cardinals hypothesis Israeli Logic Talks
 Ralf Schindler: Variants of the extender algebra and their applications Israeli Logic Talks
 Antonio Aviles: Twisted sums of spaces of continuous functions Toronto Set Theory Seminar
 Yair Hayut: Strong compactness and the filter extension property Kurt Godel Research Center
 European Set Theory Conference 2019 – registration reminder Kurt Godel Research Center
 Jing Zhang: Poset dimension and singular cardinals Carnegie Mellon Logic Seminar
 Samuel Gomes da Silva: Reductions between certain incidenceproblems and the Continuum Hypothesis Barcelona Set Theory Seminar
Upcoming conferences
 May 13: 50 Years of Set Theory in Toronto, Fields institute, May 1317, 2019
 May 30: Logic Fest in the Windy City, Chicago, May 30 – June 2, 2019
 June 19: Boise Extravaganza in Set Theory (BEST) 2019 Conference
 June 26: 12th Young Set Theory Workshop, Vienna, June 26 – 29, 2019
 July 1: 7th European Set Theory Conference, Vienna, July 15, 2019
 July 8: Berkeley conference on inner model theory, July 08–19, 2019
 July 29: Set Theory: Bridging Mathematics and Philosophy, Konstanz, July 2931, 2019
 August 11: Logic Colloquium 2019, Prague, August 11 – 16, 2019
 September 9: Settheoretic methods in topology and real functions theory, Kosice, September 913, 2019

Talks by venue
 Barcelona Set Theory Seminar (RSS)
 Boise Set Theory Seminar (RSS)
 Bonn Logic Seminar (RSS)
 Bristol Logic Seminar (RSS)
 Budapest Logic Seminar (RSS)
 Carnegie Mellon Logic Seminar (RSS)
 Dartmouth Logic Seminar (RSS)
 IMPAN working group in applications of set theory (RSS)
 Israeli Logic Talks (RSS)
 Kurt Godel Research Center (RSS)
 Logic Seminar in Turin (RSS)
 Michigan Logic Seminar (RSS)
 Morelia Topology and Set Theory Seminar (RSS)
 New York Logic Seminars (RSS)
 NUS logic seminar (RSS)
 Prague Set Theory Seminar (RSS)
 Rutgers Logic Seminar (RSS)
 Toronto Set Theory Seminar (RSS)
 UC Irvine Set Theory Seminar (RSS)
 Wrocław University of Technology (RSS)
Talks by speaker
Alan Dow Alekos Kechris Aleksander Cieślak Aleksandra Kwiatkowska Alessandro Vignati Alexei Kolesnikov Andreas Blass Andrés Caicedo Andrés Villaveces Andrew BrookeTaylor Andrew Marks Andy Zucker Antonio Avilés Anush Tserunyan Ari Brodsky Artem Chernikov Arthur Apter Arturo Antonio Martinez Asaf Karagila Asger Tornquist Ashutosh Kumar Assaf Hasson Assaf Rinot Barnabas Farkas Benjamin Miller Bill Chen Bill Mitchell Boban Velickovic Borisa Kuzeljevic Brent Cody Burak Kaya Carlos Di Prisco Carlos MartinezRanero Charles Morgan Chris Eagle Chris LambieHanson Christian Rosendal Christina Brech Clinton Conley Daisuke Ikegami Damian Sobota Dana Bartošová Daniel Soukup David Aspero David Chodounsky David J. Fernández Bretón David Marker David Schrittesser Diana Carolina Montoya Diana Ojeda Diego Alejandro Mejia Dikran Dikranjan Dilip Raghavan Dima Sinapova Egbert Thümmel Erez Shochat Erin Carmody Filippo Calderoni Frank Stephan Franklin Tall Fulgencio Lopez Garrett Ervin Gregory Cherlin Grigor Sargsyan Grzegorz Plebanek Gunter Fuchs Heike Mildenberger Hiroshi Sakai Hugh Woodin Ilijas Farah Ioannis Souldatos István Juhász Itay Neeman James Cummings Jan Grebík Jan van Mill Jay Williams Jean Larson Jindra Zapletal Jing Zhang Joan Bagaria Joel David Hamkins John Baldwin John Clemens John Krueger John Steel Jonathan Verner Jordi LopezAbad Jörg Brendle Jose Iovino Jouko Väänänen Julien Melleray Juliette Kennedy Juris Steprans Justin Moore K. P. Hart Kaethe Minden Konstantinos Tyros Lajos Soukup Laura Fontanella Leandro Aurichi Liljana Babinkostova Liuzhen Wu Luca Motto Ros Luz María García Ávila Lynn Scow Lyubomyr Zdomskyy Marcin Michalski Marcin Sabok Marion Scheepers Martin Goldstern Martin Zeman Martino Lupini Maryanthe Malliaris Masaru Kada Matteo Viale Matthew D. Foreman Melvin Fitting Menachem Kojman Menachem Magidor Merlin Carl Michael Hrusak Michal Doucha Miguel Angel Mota Miha Habic Mikhail Tkachenko Mirna Džamonja Miyamoto Tadatoshi Monroe Eskew Moti Gitik Nam Trang Natasha Dobrinen Norman Perlmutter Omer Ben Neria Omer Mermelstein Osvaldo Guzman Osvaldo Guzmán González Paul Larson Paul McKenney Peng Yinhe Peter Holy Peter Koellner Peter Koepke Peter Krautzberger Petr Simon Philip Welch Philipp Lücke Philipp Schlicht Piotr BorodulinNadzieja Piotr Koszmider Ralf Schindler Randall Holmes Rick Statman Robert Ralowski Robin TuckerDrob Rodrigo R. Dias Roman Kossak Saharon Shelah Sakaé Fuchino Salma Kuhlmann Samuel Coskey Sandra Müller Šárka Stejskalová Scott Cramer Scott Schneider Sean Cox Sebastien Vasey Sergei Artemov Shehzad Ahmed Simon Thomas Slawomir Solecki Spencer Unger Stefan Geschke Stevo Todorcevic Su Gao Sy David Friedman Szymon Zeberski Teruyuki Yorioka Thilo Weinert Timothy Trujillo Todd Eisworth Todor Tsankov Tomek Bartoszynski Toshimichi Usuba Trevor Wilson Ulises Ariet Ramos Garcia Uri Abraham Vera Fischer Victor Torres Perez Victoria Gitman Vincenzo Dimonte Wieslaw Kubis Will Boney Wojciech Stadnicki Wolfgang Wohofsky Xianghui Shi Yair Hayut Yizheng Zhu Yurii Khomskii Zoltán VidnyánszkyCategories
Recent discussions
 12th Young Set Theory Workshop, Vienna, June 26 – 29, 2019  Set Theory Talks on 6th Young Set Theory Workshop, June 1014, 2013
 12th Young Set Theory Workshop, Vienna, June 26 – 29, 2019  Set Theory Talks on 8th Young Set Theory Workshop, Jerusalem, October 2530, 2015
 12th Young Set Theory Workshop, Vienna, June 26 – 29, 2019  Set Theory Talks on 10th Young Set Theory Workshop, Edinburgh, July 10–14, 2017
 12th Young Set Theory Workshop, Vienna, June 24 – 28, 2019  Set Theory Talks on 9th Young Set Theory Workshop, Copenhagen, June 1317, 2016
 12th Young Set Theory Workshop, Vienna, June 24 – 28, 2019  Set Theory Talks on 11th Young Set Theory Workshop, Lausanne, June 25–29, 2018
 12th Young Set Theory Workshop, Vienna, June 26 – 29, 2019  Set Theory Talks on 6th Young Set Theory Workshop, June 1014, 2013
Seminar organizer’s toolbox
David Fernández Bretón earned a Ph.D. from the Department of Mathematics and Statistics of York University in Toronto, under the supervision of Juris Steprāns.
My main interests are Logic and Set Theory, especially Forcing and Large Cardinals (although my knowledge of the latter is not as deep as I would like), and their applications to Algebra and Analysis. I am currently working on the algebra and topology of the StoneČech compactification of groups, notably Abelian groups, and with idempotents in said compactification. I have also been interested in the Cardinal Invariants of the Continuum for a while.
In a much more informal fashion (pretty much as a hobby), I also like to look at alternative axiomatizations of set theory, such as NFU, and some (very basic) category theory. I am also interested in the Philosophy of Mathematics and in Ludwig Wittgenstein’s life and work.
Recent and upcoming talks by David J. Fernández Bretón
David Fernández Bretón: Ultrafilters on the rationals generated by perfect sets
Place: Fields Institute (Room 210)
Date: June 17th, 2016 (13:3015:00)
Speaker: David Fernandez Bretón
Title: Ultrafilters on the rationals generated by perfect sets
Abstract: In a 1992 paper, van Douwen defined what he calls a
“gruff ultrafilter”: an ultrafilter on the rational numbers which
is generated by perfect (this is, closed and crowded) sets; and
asked whether these ultrafilters exist, providing in the same
paper a proof that they do if cov(M)=c. continue reading…
David Fernández Bretón: d=c implies that there are gruff ultrafilters
Thursday, February 25, 4:005:30 PM at CC Little 2502 (note the nonstandard building/room!!!)
I will show a proof of the statement in the title. Recall that a gruff ultrafilter was defined by van Douwen to be an ultrafilter on the rational numbers with a base of perfect subsets (where perfect means both closed (in the topology inherited from the usual Euclidean one from the reals) and crowded (without isolated points)). continue reading…
David Fernández Bretón: Gruff ultrafilters in the Random model
Thursday, January 28, 4:005:30 PM at CC Little 2502 (note the nonstandard building/room!!!):
A gruff ultrafilter (a concept introduced by van Douwen) is an ultrafilter on the rational numbers with a base of perfect subsets (where perfect means both closed (in the topology inherited from the usual Euclidean one from the reals) and crowded (without isolated points)). continue reading…
David Fernández Bretón: An introduction to weak diamonds, II
Thursday, November 19, 2015; 16:0017:30; East Hall 3096
After having introduced the basics of weak diamond principles, we will show their usage with some examples: construction of a Suslin tree, of strongly summable ulrafilters, and of gruff ultrafilters. continue reading…
David Fernández Bretón: An introduction to weak diamonds
Thursday, November 5, 2015, 16:0017:30, 3096 East Hall.
I will introduce the basics of weak diamond principles, and show their usage with a couple of examples (construction of a Suslin tree and of a Ppoint). continue reading…
David Fernandez Breton: All that there is to know about gruff ultrafilters, II
Wednesday, September 23, 2015 — 16:00 to 17:30 — 3096 East Hall
An ultrafilter on the rational numbers is gruff if it has a base of perfect (this is, closed and without isolated points) sets. continue reading…
David Fernández Bretón: All that there is to know about gruff ultrafilters
Wednesday, September 16, 2015
3096 East Hall
16:0017:30.
Gruff ultrafilters are ultrafilters on the rational numbers that have a basis of perfect sets (according to the usual Euclidean topology). I will explain what is known about their existence, and hopefully (if there’s enough time) finish with a theorem of M. continue reading…
David Fernandez: A model of ZFC with strongly summable ultrafilters, small covering of meagre and large dominating number
Place: Fields Institute, Room 210
Date and time: Friday 23 January 2015 (13:3015:00)
Speaker: David Fernandez
Title: A model of ZFC with strongly summable ultrafilters, small covering of meagre and large dominating number. continue reading…
David Fernandez: Two microcontributions to the theory of Strongly Summable Ultrafilters
4 April 2014, 13:30–15:00
Fields institute, Room 210
Speaker: David Fernandez
Title: Two microcontributions to the theory of Strongly Summable Ultrafilters
Strongly Summable Ultrafilters are those generated by FSsets (where FS(X) is the set of all possible sums of finitely many elements from X (you can only add each element once)). continue reading…