# Just when I thought I was out

I recently pondered whether I should stop reading the few remaining mathoverflow and math.stackexchange feeds I keep in my feed reader (remember that archaic technology? I still use it heavily). Ever since I left research, I had dialed down the number of tags I was following on those wonderful sites, both because it was painful and because I lost interest (as contradictory as that may sound); in the end, all I kept were the [ultrafilter] tag on MO and the [set theory] tag on math.SE.

But I found myself brushing past even those few postings, so that yesterday I thought it was time to move on and remove them from my feed reader, de fact closing the "math" section of my feed reader, where all my research related feeds ended up. And then just as I am about to, I see this question and answer which, while neither spectacular or particular, reminded me why I once fell in love with set theory.

So, Asaf, I will call you Joey Zasa from now on.

*Comments*

**Asaf Karagila**, 2014/05/31

You’re welcome! :-)**Ioanna**, 2014/06/02

Nice question and answers there! Set theory is fun Peter, it doesn’t have to be your job for you to play with it :)**Peter**, 2014/01/06

Thanks, Ioanna. Well, when I left set theory, part of the reason was that it had stopped being fun. But I always thought our generation is lucky in the way the web helps us stay connected with our research area long after we left for other ventures (I even left a productive comment on a math.SE answer this year 😉 ).

**Peter**, 2014/06/05

Bam! Math! \[ f: X \to Y \] And $ \sqrt{2} \le 2 $**Asaf Karagila**, 2014/06/06

The first one is false in general, and the second one is false in \(\mathbb Q\) and \(\mathbb C\).

😉**Peter**, 2014/06/09

Indeed. It was just a test for MathJax rendering in the comments. I should be less careless 😉**Asaf Karagila**

Have you been dabbling with intuitionistic logic again?

“Less careless” + Law of excluded middle = “More careful”.

But he use of LEM is essential here! :-)