Proof of Lemma 6.3 in ``The crossing number of $K_{4,n}$ on the torus and the Klein bottle"

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/155889We found that Lemma 6.3 in the paper ``The crossing number of $K_{4,n}$ on the torus and the Klein bottle" is wrong.Combinatorics53C10Proof of Lemma 6.3 in ``The crossing number of $K_{4,n}$ on the torus and the Klein bottle"text