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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.

Defines:

diagonal intersection

Type of Math Object:

Definition

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Reference

## Mathematics Subject Classification

03E99*no label found*

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new question: Lorenz system by David Bankom

Oct 19

new correction: examples and OEIS sequences by fizzie

Oct 13

new correction: Define Galois correspondence by porton

Oct 7

new correction: Closure properties on languages: DCFL not closed under reversal by babou

new correction: DCFLs are not closed under reversal by petey

Oct 2

new correction: Many corrections by Smarandache

Sep 28

new question: how to contest an entry? by zorba

new question: simple question by parag

Sep 26

new question: Latent variable by adam_reith