A classical result showed by Stiebitz in 1996 stated that a graph with minimum degree $s+t+1$ contains a vertex partition $(A, B)$,  such that $G[A]$ has minimum degree at least $s$ and $G[B]$ has minimum degree at least $t$.

Motivated by this result, it was conjectured that for any non- negative real number $s$ and $t$, such that if $G$ is a non-null graph with average degree at least $s + t + 2$, then there exist a vertex partition $(A, B)$ such that $G[A]$ has average degree at least $s$ and $G[B]$ has average degree at least $t$.