A k-ranking of a graph G is a colouring Ï† : V (G) â†’ {1, . . . , k} such that any path in G with endvertices x, y fulfilling Ï†(x) = Ï†(y) contains an internal vertex z with Ï†(z) > Ï†(x). On-line rankingâ€¦ (More)

A k-ranking of a graph G is a mapping : V (G) â†’ {1, . . . , k} such that any path with endvertices x and y satisfying x = y and (x) = (y) contains a vertex z with (z) > (x). The ranking number r(G)â€¦ (More)