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of an inverse spectrum $\{X_\alpha,\omega_\alpha^\beta:\alpha\in\mathfrak A\}$

A system $x=\{x_\alpha\}$ of points $x_\alpha\in X_\alpha$ (one point from every $X_\alpha$), that is, a point of the product $\prod_{\alpha\in\mathfrak A}X_\alpha$ of the sets $X_\alpha$, such that $\omega_\alpha^\beta(x_\beta)=x_\alpha$ whenever $\beta>\alpha$.


Comments

The sets of threads of an inverse spectrum (or projective system, or inverse system) is called the (projective, inverse) limit of that spectrum (see the editorial comments to Limit).

References

[a1] R. Engelking, "General topology" , Heldermann (1989)
How to Cite This Entry:
Thread. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Thread&oldid=13432
This article was adapted from an original article by B.A. Pasynkov (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article