let C be Simple_closed_curve; for n being Nat st 0 < n holds
LMP (L~ (Cage (C,n))) = LMP (Lower_Arc (L~ (Cage (C,n))))
let n be Nat; ( 0 < n implies LMP (L~ (Cage (C,n))) = LMP (Lower_Arc (L~ (Cage (C,n)))) )
set f = Cage (C,n);
set w = ((E-bound C) + (W-bound C)) / 2;
A1:
Lower_Arc (L~ (Cage (C,n))) c= L~ (Cage (C,n))
by JORDAN6:61;
A2:
(W-bound C) + (E-bound C) = (W-bound (L~ (Cage (C,n)))) + (E-bound (L~ (Cage (C,n))))
by JORDAN1G:33;
A3:
E-bound (L~ (Cage (C,n))) = E-bound (Lower_Arc (L~ (Cage (C,n))))
by JORDAN21:20;
A4:
W-bound (L~ (Cage (C,n))) = W-bound (Lower_Arc (L~ (Cage (C,n))))
by JORDAN21:19;
assume A5:
0 < n
; LMP (L~ (Cage (C,n))) = LMP (Lower_Arc (L~ (Cage (C,n))))
then A6:
0 + 1 <= n
by NAT_1:13;
then A7:
(n -' 1) + 1 = n
by XREAL_1:235;
A8:
now LMP (L~ (Cage (C,n))) in Lower_Arc (L~ (Cage (C,n)))A9:
Center (Gauge (C,1)) <= len (Gauge (C,1))
by JORDAN1B:13;
A10:
len (Gauge (C,n)) = width (Gauge (C,n))
by JORDAN8:def 1;
A11:
(Upper_Arc (L~ (Cage (C,n)))) \/ (Lower_Arc (L~ (Cage (C,n)))) = L~ (Cage (C,n))
by JORDAN6:def 9;
assume A12:
not
LMP (L~ (Cage (C,n))) in Lower_Arc (L~ (Cage (C,n)))
;
contradictionconsider j being
Nat such that A13:
1
<= j
and A14:
j <= len (Gauge (C,n))
and A15:
LMP (L~ (Cage (C,n))) = (Gauge (C,n)) * (
(Center (Gauge (C,n))),
j)
by A5, Th20;
set a =
(Gauge (C,1)) * (
(Center (Gauge (C,1))),1);
set b =
(Gauge (C,n)) * (
(Center (Gauge (C,n))),
j);
set L =
LSeg (
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)),
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)));
A16:
(Gauge (C,1)) * (
(Center (Gauge (C,1))),1)
in LSeg (
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)),
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)))
by RLTOPSP1:68;
LMP (L~ (Cage (C,n))) in L~ (Cage (C,n))
by JORDAN21:31;
then
LMP (L~ (Cage (C,n))) in Upper_Arc (L~ (Cage (C,n)))
by A12, A11, XBOOLE_0:def 3;
then
LSeg (
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)),
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)))
meets Lower_Arc (L~ (Cage (C,n)))
by A7, A13, A14, A15, A10, JORDAN1J:62;
then consider x being
object such that A17:
x in LSeg (
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)),
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)))
and A18:
x in Lower_Arc (L~ (Cage (C,n)))
by XBOOLE_0:3;
reconsider x =
x as
Point of
(TOP-REAL 2) by A17;
A19:
1
<= Center (Gauge (C,n))
by JORDAN1B:11;
A20:
1
<= len (Gauge (C,1))
by Lm3;
then A21:
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)) `1 = ((E-bound C) + (W-bound C)) / 2
by JORDAN1A:38;
then A22:
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `1 = ((E-bound C) + (W-bound C)) / 2
by A5, A13, A14, A20, JORDAN1A:36;
then
LSeg (
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)),
((Gauge (C,n)) * ((Center (Gauge (C,n))),j))) is
vertical
by A21, SPPOL_1:16;
then A23:
x `1 = ((E-bound C) + (W-bound C)) / 2
by A17, A21, A16, SPPOL_1:def 3;
then
x in Vertical_Line (((E-bound C) + (W-bound C)) / 2)
;
then A24:
x in (Lower_Arc (L~ (Cage (C,n)))) /\ (Vertical_Line (((E-bound C) + (W-bound C)) / 2))
by A18, XBOOLE_0:def 4;
then A25:
(LMP (Lower_Arc (L~ (Cage (C,n))))) `2 <= x `2
by A2, A4, A3, JORDAN21:29;
A26:
Center (Gauge (C,n)) <= len (Gauge (C,n))
by JORDAN1B:13;
1
<= Center (Gauge (C,1))
by JORDAN1B:11;
then A27:
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)) `2 <= ((Gauge (C,n)) * ((Center (Gauge (C,n))),1)) `2
by A6, A19, A26, A9, JORDAN1A:43;
((Gauge (C,n)) * ((Center (Gauge (C,n))),1)) `2 <= ((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `2
by A13, A14, A10, A19, A26, SPRECT_3:12;
then
((Gauge (C,1)) * ((Center (Gauge (C,1))),1)) `2 <= ((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `2
by A27, XXREAL_0:2;
then A28:
x `2 <= ((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `2
by A17, TOPREAL1:4;
(LMP (L~ (Cage (C,n)))) `2 <= (LMP (Lower_Arc (L~ (Cage (C,n))))) `2
by A1, A2, A4, A3, A24, JORDAN21:13, JORDAN21:44;
then
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `2 <= x `2
by A15, A25, XXREAL_0:2;
then
((Gauge (C,n)) * ((Center (Gauge (C,n))),j)) `2 = x `2
by A28, XXREAL_0:1;
hence
contradiction
by A12, A15, A18, A22, A23, TOPREAL3:6;
verum end;
proj2 .: ((L~ (Cage (C,n))) /\ (Vertical_Line (((E-bound C) + (W-bound C)) / 2))) is bounded_below
by A2, JORDAN21:13;
hence
LMP (L~ (Cage (C,n))) = LMP (Lower_Arc (L~ (Cage (C,n))))
by A1, A2, A4, A3, A8, JORDAN21:22, JORDAN21:46; verum