Regular graph
| Graph families defined by their automorphisms | ||||
|---|---|---|---|---|
| distance-transitive | → | distance-regular | ← | strongly regular |
| ↓ | ||||
| symmetric (arc-transitive) | ← | t-transitive, t ≥ 2 | skew-symmetric | |
| ↓ | ||||
| (if connected) vertex- and edge-transitive |
→ | edge-transitive and regular | → | edge-transitive |
| ↓ | ↓ | ↓ | ||
| vertex-transitive | → | regular | → | (if bipartite) biregular |
| ↑ | ||||
| Cayley graph | ← | zero-symmetric | asymmetric | |
In graph theory, a regular graph is a graph where each vertex has the same number of neighbors; i.e. every vertex has the same degree or valency. A regular directed graph must also satisfy the stronger condition that the indegree and outdegree of each internal vertex are equal to each other. A regular graph with vertices of degree k is called a k‑regular graph or regular graph of degree k.