Midwest Computability Seminar

Part vi

The Midwest Computability Seminar is meeting remotely in the fall of 2020. The recurring Zoom link is:


Meeting ID: 997 5433 2165

Passcode: midwest

Panopto video   YouTube video

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

DATE: Tuesday, October 27th, 2020

TIME: 3:00 - 4:00 PM Central

SPEAKER: Li Ling Ko - University of Notre Dame

Fickleness and bounding lattices in the recursively enumerable Turing degrees

The ability for a recursively enumerable Turing degree d to bound certain important lattices depends on the degree's fickleness. For instance, d bounds L7 (1-3-1) if and only if d's fickleness is >ω (≥ωω). We work towards finding a lattice that characterizes the >ω2 levels of fickleness and seek to understand the challenges faced in finding such a lattice. The candidate lattices considered include those that are generated from three independent points, and upper semilattices that are obtained by removing the meets from important lattices.

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