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<H3>The Hahn-Banach Theorem for Real Vector Spaces (Isabelle/Isar)</H3>
Author: Gertrud Bauer, Technische Universität München<P>
This directory contains the proof of the Hahn-Banach theorem for real vectorspaces,
following H. Heuser, Funktionalanalysis, p. 228 -232.
The Hahn-Banach theorem is one of the fundamental theorems of functioal analysis.
It is a conclusion of Zorn's lemma.<P>
Two different formaulations of the theorem are presented, one for general real vectorspaces
and its application to normed vectorspaces. <P>
The theorem says, that every continous linearform, defined on arbitrary subspaces
(not only one-dimensional subspaces), can be extended to a continous linearform on
the whole vectorspace.
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<A NAME="bauerg@in.tum.de" HREF="mailto:bauerg@in.tum.de">bauerg@in.tum.de</A>
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