src/HOL/Hahn_Banach/README.html
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<H3>The Hahn-Banach Theorem for Real Vector Spaces (Isabelle/Isar)</H3>

Author: Gertrud Bauer, Technische Universit&auml;t M&uuml;nchen<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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<ADDRESS>
<A NAME="bauerg@in.tum.de" HREF="mailto:bauerg@in.tum.de">bauerg@in.tum.de</A>
</ADDRESS>

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