let A be Subset of (TOP-REAL 2); :: thesis: ( A is Bounded & A is Jordan implies BDD A is_inside_component_of A )
assume A1:
( A is Bounded & A is Jordan )
; :: thesis: BDD A is_inside_component_of A
then consider A1, A2 being Subset of (TOP-REAL 2) such that
A2:
( A ` = A1 \/ A2 & A1 misses A2 & (Cl A1) \ A1 = (Cl A2) \ A2 & ( for C1, C2 being Subset of ((TOP-REAL 2) | (A ` )) st C1 = A1 & C2 = A2 holds
( C1 is_a_component_of (TOP-REAL 2) | (A ` ) & C2 is_a_component_of (TOP-REAL 2) | (A ` ) ) ) )
by JORDAN1:def 2;
A3:
Down A1,(A ` ) = A1
by A2, XBOOLE_1:21;
A4:
Down A2,(A ` ) = A2
by A2, XBOOLE_1:21;
then A5:
( Down A1,(A ` ) is_a_component_of (TOP-REAL 2) | (A ` ) & Down A2,(A ` ) is_a_component_of (TOP-REAL 2) | (A ` ) )
by A2, A3;
then A6:
A1 is_a_component_of A `
by A3, CONNSP_1:def 6;
A7:
A2 is_a_component_of A `
by A4, A5, CONNSP_1:def 6;
reconsider D = A ` as non empty Subset of (TOP-REAL 2) by A1, JORDAN1:def 2;
A8:
not (TOP-REAL 2) | D is empty
;
then A9:
Down A2,(A ` ) <> {} ((TOP-REAL 2) | (A ` ))
by A5, CONNSP_1:34;
A10:
UBD A is_outside_component_of A
by A1, Th76;
then
UBD A is_a_component_of A `
by Def4;
then consider B1 being Subset of ((TOP-REAL 2) | (A ` )) such that
A11:
( B1 = UBD A & B1 is_a_component_of (TOP-REAL 2) | (A ` ) )
by CONNSP_1:def 6;
per cases
( B1 = A1 or B1 misses Down A1,(A ` ) )
by A3, A5, A11, CONNSP_1:37;
suppose A12:
B1 = A1
;
:: thesis: BDD A is_inside_component_of Athen A13:
A2 is_inside_component_of A
by A7, Def3;
then A14:
A2 c= BDD A
by Th26;
now assume
not
BDD A c= A2
;
:: thesis: contradictionthen consider x being
set such that A15:
(
x in BDD A & not
x in A2 )
by TARSKI:def 3;
consider y being
set such that A16:
(
x in y &
y in { B3 where B3 is Subset of (TOP-REAL 2) : B3 is_inside_component_of A } )
by A15, TARSKI:def 4;
consider B3 being
Subset of
(TOP-REAL 2) such that A17:
(
y = B3 &
B3 is_inside_component_of A )
by A16;
A18:
B3 is_a_component_of A `
by A17, Def3;
then consider B4 being
Subset of
((TOP-REAL 2) | (A ` )) such that A19:
(
B4 = B3 &
B4 is_a_component_of (TOP-REAL 2) | (A ` ) )
by CONNSP_1:def 6;
A20:
B3 <> {} ((TOP-REAL 2) | (A ` ))
by A8, A19, CONNSP_1:34;
(
B4 = Down A2,
(A ` ) or
B4 misses Down A2,
(A ` ) )
by A5, A19, CONNSP_1:37;
then A21:
(
B4 = Down A2,
(A ` ) or
B4 /\ (Down A2,(A ` )) = {} ((TOP-REAL 2) | (A ` )) )
by XBOOLE_0:def 7;
then A22:
(
B3 misses A1 &
B3 misses A2 )
by A3, A4, A5, A15, A16, A17, A19, CONNSP_1:37;
B3 c= A `
by A18, SPRECT_1:7;
then B3 =
B3 /\ (A1 \/ A2)
by A2, XBOOLE_1:28
.=
(B3 /\ A1) \/ (B3 /\ A2)
by XBOOLE_1:23
.=
{}
by A4, A16, A17, A19, A21, A22, XBOOLE_0:def 7
;
hence
contradiction
by A20;
:: thesis: verum end; hence
BDD A is_inside_component_of A
by A13, A14, XBOOLE_0:def 10;
:: thesis: verum end; suppose A23:
B1 misses Down A1,
(A ` )
;
:: thesis: BDD A is_inside_component_of AA24:
BDD A misses UBD A
by Th28;
A25:
(BDD A) \/ (UBD A) = A `
by Th31;
set E1 =
Down A1,
(A ` );
set E2 =
Down A2,
(A ` );
(Down A1,(A ` )) \/ (Down A2,(A ` )) = [#] ((TOP-REAL 2) | (A ` ))
by A2, A3, A4, PRE_TOPC:def 10;
then A26:
UBD A = A2
by A4, A5, A8, A11, A23, Th115;
A27:
BDD A c= A1
A1 c= BDD A
then A32:
BDD A = A1
by A27, XBOOLE_0:def 10;
BDD A is
Bounded
by A1, Th114;
hence
BDD A is_inside_component_of A
by A6, A32, Def3;
:: thesis: verum end; end;