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Mathoverflow.net news digest

  • 0 days

    Modular flow encoding and retrocausal information retrieval

    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...

  • 0 days

    Generate a subgroup lattice for $S_5$

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

  • 13 days

    Can $\gcd(n^k \pm 1, \hspace{2mm} n! \pm 1)>1$ have arbitrarily many but finitel...

    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) &...

  • 2 months

    Prove that except for $n=1$, there are more topologies of size $n$ than groups o...

    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...

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