$\forall$$a$,${\it a'}$,$b$,${\it b'}$:$\mathbb{Z}$. assoced($a$; ${\it a'}$) $\Rightarrow$ assoced($b$; ${\it b'}$) $\Rightarrow$ (divides($a$; $b$) $\Leftarrow\!\Rightarrow$ divides(${\it a'}$; ${\it b'}$))