is mentioned by

Thm* x,y:Label. Dec(x = y)	[decidable__equal_lbl]
Thm* x:Label, ls:Label List. x ls (x ls)	[assert_lbls_member]
Thm* l1,l2:Label. l1 = l2 l1 = l2	[eq_lbl_iff]
Thm* SQType(Label)	[lbl_sq]
Thm* x,y:Label. lbl_pr( < x, y > ) Label	[lbl_pair_wf2]
Thm* l1,l2:Label. l1 = l2 l1 = l2	[assert_eq_label]
Thm* x:Atom. ptn_atom(x) Label	[ptn_atom_wf3]

Try larger context: GenAutomata