$\forall$$X$:Type, $x$:chain\_master(), ${\it config}$:((Id List)$\rightarrow$$X$), ${\it seq}$:(Id$\rightarrow$Id$\rightarrow\mathbb{N}\rightarrow$$X$).
\\[0ex]case $x$ of config(${\it list}$) =$>$ ${\it config}$(${\it list}$) seq(${\it from}$,${\it to}$,${\it num}$) =$>$ ${\it seq}$(${\it from}$,${\it to}$,${\it num}$) $\in$ $X$