theorem Th15: :: TOPGEN_2:15

for T being non empty finite-weight TopSpace ex B0 being Basis of T ex f being Function of the carrier of T, the topology of T st
( B0 = rng f & ( for x being Point of T holds
( x in f . x & ( for U being open Subset of T st x in U holds
f . x c= U ) ) ) )