Precise lower bound for the number of edges of minor weight in planar maps
Precise Upper Bound for the Strong Edge Chromatic Number of Sparse Planar Graphs
We prove that every planar graph with maximum degree ∆ is strong edge (2∆−1)-colorable if its girth is at least 40 [...] +1. The bound 2∆−1 is reached at any graph that has two adjacent vertices of degree ∆.
Primitive spatial graphs and graph minors.
Problèmes ouverts. Représentation graphique d'un graphe