Proof nodes with linear position and backtracking (replaces obsolete proof_history.ML).
(* Title: HOL/Real/HahnBanach/ROOT.ML
ID: $Id$
Author: Gertrud Bauer, TU Munich
The Hahn-Banach theorem for real vector spaces (Isabelle/Isar).
*)
time_use_thy "HahnBanach";