MathOverflow

Modular flow encoding and retrocausal information retrieval — is this conjecture well-posed?
I am working on a theoretical framework involving Tomita-Takesaki modular theory in the Rindler wedge. Before investing further effort, I would like to know whether the following conjecture is mathematically well-posed, and whether there are known results...

Is there a (correct) picture available of the subgroup lattice of $S_5$, up to identifying conjugate subgroups (to avoid clutter)?

Fix an integer $k \geq 2$ and let $n \geq 2$ be integer as well. Let $\lambda_1,\lambda_2 \in \{-1, 1 \}$, and then consider the set$$S_{k}^{\lambda_1,\lambda_2}:= \{n \in \mathbb{N}\setminus\{0,1\} : \gcd(n^k+\lambda_1, \hspace{2mm} n!+\lambda_2) &...

This question was first asked here, but no answer was given.
For every positive integer $n$ let $a_n$ be the number of groups of order $n$ up to isomorphism, and let $b_n$ be the number of topological spaces of size $n$ (we are counting the points not open sets) up to homeomorphism. After looking at A001930 and...