Bjørn Kjos-Hanssen

If f and g are automorphisms of a partial order L, and a ≤ f(b) and b ≤ g(a) ... then is there an automorphism sending a to b?
(I know the answer but am curious what arguments/examples others may have. Caution: it's too hard for ChatGPT!)

I've always heard it referred to as simply "product".

If you don't know me, I'm 9, where m=3 and b=2

Ask not what this is --- ask "what is this knot?"

An "attractive" red cube in the middle of this polymer.

An example of the nonmonotonicity of optimal protein folding in the hydrophobic-polar model!

Here's an example of my online game Labbyfold. Fold proteins into their optimal configuration! math.hawaii.edu/~bjoern/?she...

Picture... or it didn't happen? 🙂

I forget the proper terminology! But the DFA is shown below. The alphabet is {0,1}. Reading 000 you go in a 3-cycle from q₀ to q₀. Given this you can fill in all edge labels. The big diagram above indicates that states (q₀,q₁,q₂) go to (q₁,q₂,q₀) when reading a 0, by having an arrow from 012 to 120.

Thanks --- here's a monoid from my book!

🍿

I kept hearing about "logical depth" so I gave in and wrote a paper about it.
math.hawaii.edu/~bjoern/logical-depth-knapsack.pdf

UNIQUE SUBSET SUM is coNP-hard. Reference?

They have different types so they can't be compared as = or not =.

No, sorry.