r:rel(), rho,ds,da1,da2,de,s,s',e,a1,a2,tr:Top.
closed_rel(r) 
(rel_mng_2(r; rho; ds; da1; de; e; s; s'; a1; tr) ~ rel_mng_2
(r; rho; ds; da2; de; e; s; s'; a2; tr))t:Term, e,s,s',a1,a2,tr:Top.
closed_term(t) ([[t]] e s s' a1 tr ~ [[t]] e s s' a2 tr)