Hello, my name is Michael O’Connor. I received my Ph.D. in mathematics from Cornell in August 2008. It was in mathematical logic, an area of mathematics that has a number of interesting nuggets, some of which I hope to explicate (for my sake as much as for anyone else’s). I now work in finance.

The header image is by Benjamin Esham and is used on the Wikipedia page on the Banach-Tarski paradox. Benjamin was kind enough to give me a version resized for this blog, so thanks a lot!

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hi.. i am just starting grad school at Cornell in CS and have been following your blog for quite sometime. If you are around in Ithaca, will be nice to meet up.Cheers!

Hereby humbly requesting “Non-Rigorous Arguments 2: …” (the highly anticipated second installment of the now-classic series)!

Hi! It is a very nice website you have here.

A couple of years ago, I wrote a “paradox”, that you might find interesting.

Have a look: http://blogoff.simonjensen.com/#post4

Best regards,

Simon Jensen

can you explain the meaning behind your blog’s name? I think I have heard it somewhere before, but Google believes that you are the only XOR’s Hammer in the universe

Dear Michael: I don’t know your email address, so I’ll ask here. I was looking a little at your paper on embedding the free Heyting algebra on countably many generators into the free Heyting algebra on two generators, and wondered if you’d considered whether there exists a free cocomplete Heyting algebra on two generators. (I want morphisms of cocomplete Heyting algebras to preserve finite meets, implication, and arbitrary joins.) I ask because the free cocomplete Heyting algebra on countably many generators does not exist (as a set). Please feel free to email me if you have some idea!

I enjoy your posts and check daily even though it’s been over a year since your last post. I hope you haven’t given up on XOR’s Hammer.