uset
uset edom;
uset dom;
uset closure;
static uset all_dom_sets;
static uset all_closure_sets;
static uset all_edge_sets;
uset x;
memset(root->et.edom, 0, edgewords * sizeof(*(uset)0));
memset(root->ef.edom, 0, edgewords * sizeof(*(uset)0));