I'm trying to prove some stuff that involves the projection map, say p:X x Y ->X. But I need to know if it's continuous. If a map is continuous, then the preimage of a open/closed set is open/closed.(adsbygoogle = window.adsbygoogle || []).push({});

The problem is, what do open sets in X x Y look like? I know what the basis elements are, and the open sets would be arbitrary unions and finite intersections, but is there any way to generalize?

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# Homework Help: Topology, projection map

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