let A, P be Subset of (TOP-REAL 2); :: thesis: ( P is compact & |[(- 1),0]|,|[1,0]| realize-max-dist-in P & A is_inside_component_of P implies A c= closed_inside_of_rectangle ((- 1),1,(- 3),3) )
assume that
A1: P is compact and
A2: |[(- 1),0]|,|[1,0]| realize-max-dist-in P and
A3: A is_inside_component_of P ; :: thesis: A c= closed_inside_of_rectangle ((- 1),1,(- 3),3)
let x be object ; :: according to TARSKI:def 3 :: thesis: ( not x in A or x in closed_inside_of_rectangle ((- 1),1,(- 3),3) )
assume that
A4: x in A and
A5: not x in closed_inside_of_rectangle ((- 1),1,(- 3),3) ; :: thesis: contradiction
P c= closed_inside_of_rectangle ((- 1),1,(- 3),3) by A2, Th71;
then A6: (closed_inside_of_rectangle ((- 1),1,(- 3),3)) ` c= P ` by SUBSET_1:12;
reconsider x = x as Point of (TOP-REAL 2) by A4;
A7: ( not - 1 <= x `1 or not x `1 <= 1 or not - 3 <= x `2 or not x `2 <= 3 ) by A5;
per cases ( 0 <= x `1 or x `1 < 0 ) ;
suppose A8: 0 <= x `1 ; :: thesis: contradiction
end;
suppose A12: x `1 < 0 ; :: thesis: contradiction
end;
end;