Paper 4, Section I, 2F2 F

Analysis and Topology | Part IB, 2021

Let XX be a topological space with an equivalence relation, X~\tilde{X} the set of equivalence classes, π:XX~\pi: X \rightarrow \tilde{X}, the quotient map taking a point in XX to its equivalence class.

(a) Define the quotient topology on X~\tilde{X} and check it is a topology.

(b) Prove that if YY is a topological space, a map f:X~Yf: \tilde{X} \rightarrow Y is continuous if and only if fπf \circ \pi is continuous.

(c) If XX is Hausdorff, is it true that X~\tilde{X} is also Hausdorff? Justify your answer.

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