Hi, I have the follow question:

Probe that, if and are closet sets in , and the restriction of the map to is proper, then is closed.

Def: Let be closet subsets of , We shall say the restriction of the map

to is proper if, for any , there is such that and imply that for .

Thanks for you help.

PS: edited: in the first line, change: proper to closed. Tnaks InvisibleMan