let empty_env = {
model_cardinal = 0;
var_terms = Term.Set.empty;
max_id_vars = 0;
nb_vars = 0;
perm_procs = [];
perm_states = [];
first_proc = 0;
extra_proc = 0;
all_procs = [];
proc_ids = [];
id_terms = HT.create 0;
id_true = 0;
id_false = 0;
st_trs = [];
low_int_abstr = 0;
up_int_abstr = 0;
pinf_int_abstr = 0;
minf_int_abstr = 0;
proc_substates = HLI.create 0;
reverse_proc_substates = HI.create 0;
partial_order = [];
table_size = 0;
explicit_states = HST.create 0;
states = [];
}