theorem Th4: :: KURATO_1:4

for T being non empty TopSpace
for A being Subset of T holds
( A ` in Kurat14Set A & (A `) - in Kurat14Set A & ((A `) -) ` in Kurat14Set A & (((A `) -) `) - in Kurat14Set A & ((((A `) -) `) -) ` in Kurat14Set A & (((((A `) -) `) -) `) - in Kurat14Set A & ((((((A `) -) `) -) `) -) ` in Kurat14Set A )