On $2$-factors of Hamiltonian graphs

Abstract

Let $k\ge 2$. We show that, for a sufficiently small $\epsilon >0$, any sufficiently large $n$-vertex Hamiltonian graph of minimum degree at least $n^{1-\epsilon }$ contains a $2$-factor consisting of exactly $k$ cycles. This is the first minimum-degree condition which is polynomially smaller than linear. Our methods yield an analogous result when the host graph is not required to contain a Hamilton cycle, but only a $2$-factor consisting of at most $k$ cycles; this answers a question of Bucić, Jahn, Pokrovskiy and Sudakov.