Cho–Hyun–O–Park spectral-radius conjecture for [a,b]-factors

Let $a$ and $b$ be positive integers with $a\le b$, and let $G$ be a finite undirected simple connected graph of order $n$ satisfying

$$n\ge a+1,\qquad na\equiv 0\pmod{2}.$$

For a graph $H$, write $\rho(H)$ for its spectral radius, and call a spanning subgraph an $[a,b]$-factor if every vertex has degree between $a$ and $b$ in that subgraph. Cho–Hyun–O–Park conjecture. If

$$\rho(G)>\rho\bigl(K_{a-1}\vee(K_{n-a}\cup K_1)\bigr),$$

then $G$ contains an $[a,b]$-factor. This is a proposed spectral-radius sufficient condition for the existence of bounded-degree spanning factors; its resolution is not supplied in the source.