Quotient Space - Definition

Definition

Let (X,τX) be a topological space, and let ~ be an equivalence relation on X. The quotient space, is defined to be the set of equivalence classes of elements of X:

equipped with the topology where the open sets are defined to be those sets of equivalence classes whose unions are open sets in X:

Equivalently, we can define them to be those sets with an open preimage under the quotient map which sends a point in X to the equivalence class containing it.

The quotient topology is the final topology on the quotient space with respect to the quotient map.

Read more about this topic:  Quotient Space

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