2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/199845Motivated by the description of the graphene electronic structure in terms of the relativistic Dirac equation, a generalization to four dimensions yields a strictly local fermion action describing two species and possessing an exact chiral symmetry. This is the minimum number of species required by the well known ``no-go'' theorems.10 pages, 1 figure. Revision adds more references and adds minor clarifications. Version to appear in JHEPHigh Energy Physics - LatticeOther Condensed Mattertext