theorem Th3: :: KURATO_1:3

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 )