Tag: monstrous moonshine

  • Lockdown reading : SNORT

    In this series I’ll mention some books I found entertaining, stimulating or comforting during these Corona times. Read them at your own risk. This must have been the third time I’ve read The genius in by basement – The biography of a happy man by Alexander masters. I first read it when it came out […]

  • Monstrous dessins 2

    Let’s try to identify the $\Psi(n) = n \prod_{p|n}(1+\frac{1}{p})$ points of $\mathbb{P}^1(\mathbb{Z}/n \mathbb{Z})$ with the lattices $L_{M \frac{g}{h}}$ at hyperdistance $n$ from the standard lattice $L_1$ in Conway’s big picture. Here are all $24=\Psi(12)$ lattices at hyperdistance $12$ from $L_1$ (the boundary lattices): You can also see the $4 = \Psi(3)$ lattices at hyperdistance $3$…

  • the monstrous moonshine picture – 1

    We’re slowly closing in on the elusive moonshine picture, which is the subgraph of Conway’s Big Picture needed to describe all 171 moonshine groups. About nine years ago I had a first go at it, drawing a tiny fraction of it, just enough to understand the 9 moonshine groups appearing in Duncan’s realization of McKay’s…