This score reflects both the level of the required concepts and the difficulty of the solution.Ce score tient compte à la fois du niveau des notions nécessaires et de la difficulté de la résolution.
1–10First steps / middle schoolPremiers pas / collège
Let X be a non-empty set. Show that the function d:X×X→R such that: ∀x,y∈X,d(x,y)={10 if x=y otherwise is a metric on any set X. It is called the discrete metric.