We show that the continuous maps out of a quotient space are precisely the continuous maps before taking quotient which descend to the quotient. For notes, see here: www.homepages.ucl.ac.uk/~ucahj...
Just to make sure, the proof of the existance of Fbar given the fact that F depends only on the equivalence classes follows from the following construction: for every A in X/~, we take "a" in A, and define Fbar(A) as F(a). The construction is consistant as if we had took any other "b" in A, as we would then have a~b, therefore F(b)=F(a)=Fbar(A) by hypothesis. That's the idea?
Yes, that's why Fbar exists as a map of sets. The point is then that it is continuous. This works because the quotient topology is defined to make it continuous.
Great series, keep on!
Just to make sure, the proof of the existance of Fbar given the fact that F depends only on the equivalence classes follows from the following construction: for every A in X/~, we take "a" in A, and define Fbar(A) as F(a). The construction is consistant as if we had took any other "b" in A, as we would then have a~b, therefore F(b)=F(a)=Fbar(A) by hypothesis. That's the idea?
Yes, that's why Fbar exists as a map of sets. The point is then that it is continuous. This works because the quotient topology is defined to make it continuous.