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Publication 15-CNA-025

Sharp $N^{3/4}$ Law for the Minimizers of the Edge-Isoperimetric Problem on the Triangular Lattice

Elisa Davoli
Department of Mathematics
University of Vienna
Oskar-Morgenstern-Platz 1
1090 Vienna, Austria
elisa.davoli@univie.ac.at

Paolo Piovano
Faculty of Mathematics
University of Vienna
Oskar-Morgenstern
A-1090 Vienna, Austria
paolo.piovano@univie.ac.at

Ulisse Stefanelli
Faculty of Mathematics
University of Vienna
Oskar-Morgenstern
A-1090 Vienna, Austria
ulisse.stefanelli@univie.ac.at

Abstract: We investigate the Edge-Isoperimetric Problem (EIP) for sets of $n$ points in the triangular lattice by emphasizing its relation with the emergence of the Wulff shape in the crystallization problem. By introducing a suitable notion of perimeter and area, EIP minimizers are characterized as extremizers of an isoperimetric inequality: they attain maximal area and minimal perimeter among connected congurations. The maximal area and minimal perimeter are explicitly quantied in terms of $n$. In view of this isoperimetric characterizations EIP minimizers $Mn$ are seen to be given by hexagonal congurations with some extra points at their boundary. By a careful computation of the cardinality of these extra points, minimizers Mn are estimated to deviate from such hexagonal congurations by at most $K_t n^{3/4} +o(n^{3/4})$ points. The constant Kt is explicitly determined and shown to be sharp.

Get the paper in its entirety as  15-CNA-025.pdf


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