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Homediagonal intersection

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# diagonal intersection

If $\langle S_{i}\rangle_{{i<\alpha}}$ is a sequence then the *diagonal intersection*, $\Delta_{{i<\alpha}}S_{i}$ is defined to be $\{\beta<\alpha\mid\beta\in\bigcap_{{\gamma<\beta}}S_{\gamma}\}$.

That is, $\beta$ is in $\Delta_{{i<\alpha}}S_{i}$ if it is contained in the first $\beta$ members of the sequence.

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diagonal intersection

Type of Math Object:

Definition

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Reference

## Mathematics Subject Classification

03E99*no label found*

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