Examples -> Thinking Operations -> Graph Theory -> Directed and Undirected Graphs

In a company of six people, everyone was asked how many acquaintances they had (the acquaintances are mutual). Response of the first five respondents: 5, 4, 3, 2, 1. |

Members of a six-person table company: Anna, Balázs, Cili, Dezső, Egon and Fruzsina. Each of them knows exactly three other people in the company. Cili knows Dezső and Egon, and Anna doesn't know either Balázs or Dezső. |