for T being non empty TopSpace
for A being non empty Subset of T
for B1, B2, C1, C2 being Subset of T st B1 is_a_component_of A & B2 is_a_component_of A & C1 is_a_component_of A & C2 is_a_component_of A & B1 \/ B2 = A & C1 \/ C2 = A holds
{B1,B2} = {C1,C2}