Part iii

The Midwest Computability Seminar is meeting remotely in the fall of 2021. The recurring Zoom link is:

https://notredame.zoom.us/j/99754332165?pwd=RytjK1RFZU5KWnZxZ3VFK0g4YTMyQT09

Meeting ID: 997 5433 2165

Passcode: midwest

Vittorio Cipriani: slides Panopto video YouTube video

David Webb: slides Panopto video YouTube video

This session will be held jointly with the Computability Theory and Applications Online Seminar.

DATE: Monday, October 11th, 2021

TIME: 3:30 - 4:30 PM Central Time

We will have two speakers:

SPEAKER: Vittorio Cipriani - University of Udine

TITLE: Cantor-Bendixson Theorem in the Weihrauch lattice

ABSTRACT: In this talk we will study the Cantor-Bendixson theorem using the framework of Weihrauch reducibility. (Variations of) this theorem falls into the highest of the big-five axiom systems of reverse mathematics, namely Π

We will continue in this direction showing (non) reductions between problems related to the Cantor-Bendixson theorem with particular attention paid to classify them for every computable Polish space

This is joint work with Alberto Marcone and Manlio Valenti.

SPEAKER: David Webb - University of Hawaiʻi at Mānoa

TITLE: Under what reducibilities are KLR and MLR Medvedev equivalent?

ABSTRACT: Motivated by the observation that one half of a Kolmogorov-Loveland random is Martin-Löf random, we consider the problem of outputting (Martin-Löf) random bits given a pair of oracles, an unknown member of which is itself random. We show that a truth-table reduction can be used to do this, so that KLR and MLR are truth-table Medvedev equivalent. We also investigate whether even stronger reducibilities can be used, obtaining negative results for linear, positive, and bounded truth-table reducibilities.

- September 13th, 2021 Rachael Alvir - University of Notre Dame / Josiah Jacobsen-Grocott - University of Wisconsin
- September 27th, 2021 Benoit Monin -
Créteil University

- October 25th, 2021: Sarah Reitzes - University of Chicago / Diego Rojas - Iowa State University
- November 8th, 2021: Cristóbal Rojas - Pontifical Catholic University of Chile
- November 22nd, 2021: Elvira Mayordomo - University of Zaragoza
- December 6th, 2021: Francesca Zaffora Blando - Carnegie Mellon University

- Sept 23rd 2008 Antonio Montalbán - Logan Axon - Joe Miller
- Nov 11th 2008 Chris Conidis - Keng Meng (Selwyn) Ng - Peter Gerdes
- Feb 3rd 2009 David Diamondstone - Bart Kastermans - Richard A. Shore
- April 21st 2009 Dan Turetsky - Julia Knight - Ted Slaman
- Sept 29th 2009 Carl Jockusch - Rachel Epstein - Rebecca Weber
- Jan 26th 2010 Sara Quinn - John Wallbaum - Steffen Lempp - Reed Solomon
- May 11th 2010 Adam Day - Liang Yu - Rod Downey - Boris Zilber
- Sept 28th 2010 Maurice Chiodo - Peter Gerdes - Damir Dzhafarov - Andy Lewis
- Feb 15th 2011 Uri Andrews - Paola D'Aquino - David Diamondstone - Christopher Porter - Rebecca Steiner
- Nov 1st 2011 Mingzhong Cai - Chris Conidis - Stephen Flood - Jeff Hirst - Asher Kach
- Nov 15th 2012 Achilles Beros - Rod Downey - Jesse Johnson - Sam Sanders - Steven VanDendriessche - Matthew Wright
- April 2nd 2013 Howard Becker - Denis Hirschfeldt - Paul Schupp
- October 1st 2013 Peter Cholak - Mushfeq Khan - Victor Ocasio-González - Jonathan Stephenson
- April 29th, 2014 Rod Downey - Noam Greenberg - Gregory Igusa - Alexander Melnikov - Kyle Riggs
- September 30th, 2014 Eric Astor - Quinn Culver - Jack Lutz - Timothy McNicholl
- February 17th, 2015 Carl Jockusch - Julia Knight - Steffen Lempp
- January 28th, 2016 Reese Johnston - Rutger Kuyper - Mariya Soskova - Mars Yamaleev
- October 22nd and 23rd, 2016 Special Meeting in Honor of Carl Jockusch's 75th Birthday
- March 16th, 2017 Greg Igusa - Jack Lutz - Sasha Melnikov - Reed Solomon
- October 24th, 2017 Noah Schweber - Don Stull - Dan Turetsky - Rose Weisshaar
- April 17th, 2018 Peter Cholak - Meng-Che "Turbo" Ho - Ethan McCarthy - Joe Miller
- October 9th, 2018 Uri Andrews - Timothy McNicholl - Alexandra Soskova
- April 18th, 2019 Wesley Calvert - Russell Miller - Steffen Lempp
- February 11th, 2020 Rachael Alvir - Tejas Bhojraj - Jun Le Goh - Neil Lutz
- August - December, 2020 Nine Online Talks
- February - May, 2021 Seven Online Talks

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