Title: Limit of the sandpile groupThe sandpile group is a finite abelian group defined for any graph. It is ofspecial interest for the piece of the lattice bounded by some convex domain. There arestrong indications that there is a limit for these groups when one fixes the domain andsends the mesh of the lattice to zero. Until recently, nobody was able tomake rigorous sense of this vague statement. Here is what we are suggesting: 1) for a given mesh, define a visual-type heuristic metric on the sandpile; 2) look at the persistence diagrams and whether they stabilise when mesh vanishes.

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