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Homework Statement
Let p : X --> Y be a closed, continuous and surjective map. Show that if X is normal, so is Y.
The Attempt at a Solution
I used the following lemma:
X is normal iff given a closed set A and open set U containing A, there is an open set V containing A and whose closure is contained in U.
So, let A be a closed set in Y, and U some neighborhood of A. By continuity, f^-1(A) is closed in X, and f^-1(U) is open in X. Further on, f^-1(U) is an open neighborhood of f^-1(A), since it contains f^-1(A). If we apply the lemma above to these sets, we can find an open set V which satisfies the criterion, since X is regular. Since p is a closed map, the image of Cl(V) is closed, and since all the inclusions remain preserved, Y is normal.
By the way, just to check, the requirement for p to be surjective was because we have chosen a set in Y, and surjectivity guarantees that this set has a well-defined preimage, right?
Thanks in advance.