1. The Baire category theorem - Aarhus Universitet
1. The Baire category theorem - Aarhus Universitet
1. The Baire category theorem - Aarhus Universitet
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Definition of first and second <strong>category</strong><br />
Second <strong>category</strong><br />
A set A ⊆ S is of second <strong>category</strong> when it is not of the first<br />
<strong>category</strong>.<br />
Via the <strong>Baire</strong> <strong>category</strong> <strong>theorem</strong> we will become able to give many<br />
examples - for example show that R is of the second <strong>category</strong> as a<br />
subset of itself. (As well as [0,1] ⊆ R).<br />
Subsequently we shall then see why the notion is usefull !<br />
Philosophically a set of second <strong>category</strong> is a large subset of S from<br />
the topological point of view.<br />
Klaus Thomsen <strong>1.</strong> <strong>The</strong> <strong>Baire</strong> <strong>category</strong> <strong>theorem</strong>