Consider the following result (Lemma 4.4.4 from "Topics in Galois Theory" byJean-Pierre Serre, Course at Harvard University, Fall 1988).
Lemma: Let $G$ be a transitive subgroup of $S_n$ which is generated by cycles of prime orders. Then:
- $G$ is primitive.
- If $G$ contains a transposition, then $G = S_n.$
- If $G$ contains a $3$-cycle, then $G = A_n$ or $S_n.$
Does it mean
- "generated by cycles of prime order"? Iimplies the inertia group at any ramified prime is of prime order? Kindly help.
I guess you are assuming $G$ is transitive. Otherwise there are obvious counterexamples, as indicated in the comments.
There are also transitive counterexamples. For example, the maximal imprimitive group $G = S_3 \wr S_3 = S_3^3 \rtimes S_3 \le S_9$ is generated by a transposition and a $9$-cycle.