+lmm_constraint_t lmm_get_cnst_from_var(lmm_system_t sys, lmm_variable_t var, int num);
+int lmm_get_number_of_cnst_from_var(lmm_system_t sys, lmm_variable_t var);
+
+void *lmm_constraint_id(lmm_constraint_t cnst);
+void *lmm_variable_id(lmm_variable_t var);
+