Blog

Recently the following question came up in tutorial as I had a student looking at ordinal arithmetic.  Basically, you want to show that if an ordinal is divisible on the right by 2 and by 3, then it...

Roy Shalev is finishing his doctorate working with Assaf Rinot at Bar Ilan University, and in this paper posted to ArXiv yesterday he answers a question left open by our work with Cummings and Moore...

My paper  The Pseudopower Dichotomy  is in the latest issue of the Journal of Symbolic Logic .  I like to think of the main theorem as a ZFC result in classical cardinal arithmetic that only becomes...

Here is a stash of notes I prepared prior to my oral comprehensive exam at Michigan back in 1990 or so.  They are based on a course taught by my advisor, Andreas Blass.  These represent a young grad...

Today marks the end of teaching for Fall semester 2023.  In my set theory course, I spent the day contextualizing some of the questions I put on their take-home final.  One of the questions has them...

I am just trying out this blog as a space to disseminate some notes I've written up over the years.  For example, this short one writes up an old result of Galvin and Shelah showing   \(2^{\aleph_0}...

A revised version of our paper with James Cummings and Justin Moore on large minimal non- \(\sigma\) -scattered linear orderings is available and attached to this post.  We have submitted to  Advances in ...

I am teaching a graduate-level introduction to set theory course this semester, and we got to spend some time with one of my favorite set-theory facts:  the Continuum Hypothesis holds if and only if...