Quick question. Classically the harmonic oscillator Hamiltonian is often written 1 2 ( p 2 + q 2), while quantum mechanically it gets some extra ‘ground state energy’ making the Hamiltonian ...

Did you know that Lawvere did classified work on arms control in the 1960s, back when he was writing his thesis? You can read more here: Yes, that’s right. For technical reasons the n-Category Café ...

• a 2-rig over a field k is a Cauchy complete k -linear symmetric monoidal category is a line object if there’s an object y with x ⊗ y ≅ I. is a bosonic line object if it is a line object and the ...

I’d like to share here a personal project which might be of interest to the readers of this blog: the Clowder Project. Clowder is a wiki and reference work for category theory built using the same ...

guest post by Emily de Oliveira Santos I’d like to share here a personal project which might be of interest to the readers of this blog: the Clowder Project. Clowder is a wiki and reference work for ...

Announcing the Clowder Project: a wiki and reference work for category theory built using the same general infrastructure and tag system of the Stacks Project.

July 2025's Entries The Duflo Isomorphism and the Harmonic Oscillator Hamiltonian Can the Duflo isomorphism explain the extra 1/2 in the Hamiltonian for the quantum harmonic oscillator? The Clowder ...

Why Mathematics is Boring I don’t really think mathematics is boring. I hope you don’t either. But I can’t count the number of times I’ve launched into reading a math paper, dewy-eyed and eager to ...

These are some lecture notes for a 4 1 2 -hour minicourse I’m teaching at the Summer School on Algebra at the Zografou campus of the National Technical University of Athens. To save time, I am ...