assume A6:
S ` <> {}
; :: thesis: ( for A1, A2 being Subset of (TOP-REAL 2) holds
( not S ` = A1 \/ A2 or not A1 misses A2 or not (Cl A1) \ A1 = (Cl A2) \ A2 or not A1 is_a_component_of S ` or not A2 is_a_component_of S ` ) or S is Jordan )
given A1, A2 being Subset of (TOP-REAL 2) such that A7:
S ` = A1 \/ A2
and
A8:
A1 misses A2
and
A9:
(Cl A1) \ A1 = (Cl A2) \ A2
and
A10:
A1 is_a_component_of S `
and
A11:
A2 is_a_component_of S `
; :: thesis: S is Jordan
thus
S ` <> {}
by A6; :: according to JORDAN1:def 2 :: thesis: ex b1, b2 being Element of bool the carrier of (TOP-REAL 2) st
( S ` = b1 \/ b2 & b1 misses b2 & (Cl b1) \ b1 = (Cl b2) \ b2 & ( for b3, b4 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b3 = b1 or not b4 = b2 or ( b3 is_a_component_of (TOP-REAL 2) | (S ` ) & b4 is_a_component_of (TOP-REAL 2) | (S ` ) ) ) ) )
reconsider a1 = A1, a2 = A2 as Subset of (TOP-REAL 2) ;
take
a1
; :: thesis: ex b1 being Element of bool the carrier of (TOP-REAL 2) st
( S ` = a1 \/ b1 & a1 misses b1 & (Cl a1) \ a1 = (Cl b1) \ b1 & ( for b2, b3 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b2 = a1 or not b3 = b1 or ( b2 is_a_component_of (TOP-REAL 2) | (S ` ) & b3 is_a_component_of (TOP-REAL 2) | (S ` ) ) ) ) )
take
a2
; :: thesis: ( S ` = a1 \/ a2 & a1 misses a2 & (Cl a1) \ a1 = (Cl a2) \ a2 & ( for b1, b2 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b1 = a1 or not b2 = a2 or ( b1 is_a_component_of (TOP-REAL 2) | (S ` ) & b2 is_a_component_of (TOP-REAL 2) | (S ` ) ) ) ) )
thus
S ` = a1 \/ a2
by A7; :: thesis: ( a1 misses a2 & (Cl a1) \ a1 = (Cl a2) \ a2 & ( for b1, b2 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b1 = a1 or not b2 = a2 or ( b1 is_a_component_of (TOP-REAL 2) | (S ` ) & b2 is_a_component_of (TOP-REAL 2) | (S ` ) ) ) ) )
thus
a1 /\ a2 = {}
by A8, XBOOLE_0:def 7; :: according to XBOOLE_0:def 7 :: thesis: ( (Cl a1) \ a1 = (Cl a2) \ a2 & ( for b1, b2 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b1 = a1 or not b2 = a2 or ( b1 is_a_component_of (TOP-REAL 2) | (S ` ) & b2 is_a_component_of (TOP-REAL 2) | (S ` ) ) ) ) )
thus
(Cl a1) \ a1 = (Cl a2) \ a2
by A9; :: thesis: for b1, b2 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b1 = a1 or not b2 = a2 or ( b1 is_a_component_of (TOP-REAL 2) | (S ` ) & b2 is_a_component_of (TOP-REAL 2) | (S ` ) ) )
( ex B being Subset of ((TOP-REAL 2) | (S ` )) st
( B = a1 & B is_a_component_of (TOP-REAL 2) | (S ` ) ) & ex B being Subset of ((TOP-REAL 2) | (S ` )) st
( B = a2 & B is_a_component_of (TOP-REAL 2) | (S ` ) ) )
by A10, A11, CONNSP_1:def 6;
hence
for b1, b2 being Element of bool the carrier of ((TOP-REAL 2) | (S ` )) holds
( not b1 = a1 or not b2 = a2 or ( b1 is_a_component_of (TOP-REAL 2) | (S ` ) & b2 is_a_component_of (TOP-REAL 2) | (S ` ) ) )
; :: thesis: verum