src/ZF/ROOT.ML

remove lemma ideal_completion.principal_induct2, use principal_induct twice instead

(*  Title:      ZF/ROOT.ML
    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
    Copyright   1993  University of Cambridge

Zermelo-Fraenkel Set Theory on top of classical First-Order Logic.
This theory is the work of Martin Coen, Philippe Noel and Lawrence
Paulson.
*)

use_thys ["Main", "Main_ZFC"];