Suggest an editImprove this articleRefine the answer for “What does "adjacency" of vertices in a graph mean?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**Adjacency of vertices** means that **two vertices are connected by an edge**. **Key point:** adjacency is a sign of a direct connection: vertices are considered adjacent if there is an edge between them.Shown above the full answer for quick recall.Answer (EN)Image**Adjacency of vertices** means that **two vertices are connected by an edge**. If there is an edge between vertices **A** and **B**, then: - In an undirected graph - **A and B are adjacent** (A ↔ B). - In a directed graph - • if there is an edge **A → B**, then **B is adjacent to A in the direction from A to B**, • but not necessarily the other way around. --- **Examples:** - In a social network: if two users are "friends", their vertices are adjacent. - On a route: if there is a road between cities, the cities are adjacent. --- **Adjacent vertices** are often stored in an **adjacency list** - each vertex has a record of all the vertices it is connected to. --- **Summary:** adjacency is a sign of a direct connection: vertices are considered adjacent if there is an edge between them.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.