Answered: Problem 5. Let X be a topological…

Problem 5. Let X be a topological space; let A be a subset of X. Suppose that for each I E A there is an open set U containing x such that U C A. Show that A is open in X.

Elements Of Modern Algebra

8th Edition

ISBN:9781285463230

Author:Gilbert, Linda, Jimmie

Publisher:Gilbert, Linda, Jimmie

Chapter3: Groups

Section3.1: Definition Of A Group

Problem 42E: 42. For an arbitrary set , the power set was defined in Section by , and addition in was...

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Problem 5. Let X be a topological space; let A be a subset of X. Suppose that for each
I E A there is an open set U containing x such that U C A. Show that A is open in X.

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