2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/147446Renormalization group equations and a phase diagram are derived for a system of two chains with a single-electron hopping between chains in order to correct the results of a recent paper by F.~V.~Kusmartsev, A.~Luther, and A.~Nersesyan, Pis'ma v Zh.\ Exp.\ Teor.\ Fiz.\ {\bf 55}, 692 (1992) [JETP Lett.\ {\bf 55}, 724 (1992)].3 pages + 1 figure (appended), pure LaTeXCondensed Mattertext