theorem Th17: :: URYSOHN3:17

for T being non empty normal TopSpace
for A, B being closed Subset of T st A <> {} & A misses B holds
for G being Rain of A,B
for r1 being Element of DOM st 0 < r1 holds
for p being Point of T st r1 < (Thunder G) . p holds
not p in (Tempest G) . r1