A new short proof of Fan Theorem
Kewen Zhao · Journal of Discrete Mathematical Sciences and Cryptography · 2013
We give a new shorter proof of the following theorem: Let G be a 2-connected graph of order n. If max {d (u); d (v)} ≥ c/2 for any two vertices u and v with d (u; v) = 2, then the circumference of G is at least c, where 3 ≤ c ≤ n and d (u; v) is the distance between vertices u and v in G. We also propose some problems.