:: deftheorem Def3 defines Theta WAYBEL29:def 3 :

for X, Y being non empty TopSpace

for b_{3} being Function of (InclPoset the topology of [:X,Y:]),(ContMaps (X,(Sigma (InclPoset the topology of Y)))) holds

( b_{3} = Theta (X,Y) iff for W being open Subset of [:X,Y:] holds b_{3} . W = (W, the carrier of X) *graph );

for X, Y being non empty TopSpace

for b

( b