Suppose $(p_1, ..., p_n)$ and $(q_1, ..., q_n)$ are two (non-strictly) decreasing sequences of positive real numbers. We say that $(q_1, ..., q_n)$ dominates $(p_1, ..., p_n)$ if $q_n \geq p_n$, $q_n+q_{n-1} \geq p_n+p_{n-1}$, ..., $q_n + ... + q_2 \geq p_n + ... + q_2$, $q_n + ... + q_1 = p_n + ... + q_1$.

For a vector bundle $F$ consider its slope $\mu(F)=deg(F)/rk(F)$. For a vector bundle $E$ with Harder-Narasimhan filtration $0 \neq E_1 \subset E_2 \subset ... \subset E_m = E$ we consider the sequence $\mu(E_1),...,\mu(E_1), ..., \mu(E_m/E_{m-1}), ..., \mu(E_m/E_{m-1})$, where $\mu(E_i/E_{i-1})$ is repeated $rk(E_i/E_{i-1})$ times, and call this sequence the degree of the Harder-Narasimhan filtration of $E$.

Suppose that $A \subset B$ are two vector bundles of the same rank $n$ such that $deg B = deg A + 1$. Assume that the degree of the Harder-Narasimhan filtration of $B$ is dominated by a (non-strictly) decreasing integer sequence $(d_1, ..., d_n)$ such that $d_1>d_2$. Is it true that then the degree of the Harder-Narasimhan filtration of $A$ is dominated by $(d_1-1, d_2, ..., d_n)$?