let n be Element of NAT ; :: thesis: for C being connected compact non horizontal non vertical Subset of (TOP-REAL 2)
for i, j, k being Element of NAT st 1 <= j & j <= k & k <= len (Gauge C,n) & 1 <= i & i <= width (Gauge C,n) & (Gauge C,n) * j,i in L~ (Lower_Seq C,n) & (Gauge C,n) * k,i in L~ (Upper_Seq C,n) holds
ex j1, k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )

let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); :: thesis: for i, j, k being Element of NAT st 1 <= j & j <= k & k <= len (Gauge C,n) & 1 <= i & i <= width (Gauge C,n) & (Gauge C,n) * j,i in L~ (Lower_Seq C,n) & (Gauge C,n) * k,i in L~ (Upper_Seq C,n) holds
ex j1, k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )

let i, j, k be Element of NAT ; :: thesis: ( 1 <= j & j <= k & k <= len (Gauge C,n) & 1 <= i & i <= width (Gauge C,n) & (Gauge C,n) * j,i in L~ (Lower_Seq C,n) & (Gauge C,n) * k,i in L~ (Upper_Seq C,n) implies ex j1, k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} ) )

assume that
A1: ( 1 <= j & j <= k & k <= len (Gauge C,n) ) and
A2: ( 1 <= i & i <= width (Gauge C,n) ) and
A3: (Gauge C,n) * j,i in L~ (Lower_Seq C,n) and
A4: (Gauge C,n) * k,i in L~ (Upper_Seq C,n) ; :: thesis: ex j1, k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )

set G = Gauge C,n;
set s = ((Gauge C,n) * 1,i) `2 ;
set f = (Gauge C,n) * j,i;
set e = (Gauge C,n) * k,i;
set w1 = inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))));
set p = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|;
set w2 = sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))));
set q = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|;
A5: len (Gauge C,n) = width (Gauge C,n) by JORDAN8:def 1;
A6: Upper_Seq C,n is_sequence_on Gauge C,n by JORDAN1G:4;
A7: (Gauge C,n) * k,i in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by RLTOPSP1:69;
then A8: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) meets L~ (Upper_Seq C,n) by A4, XBOOLE_0:3;
A9: j <= width (Gauge C,n) by A1, A5, XXREAL_0:2;
then A10: [j,i] in Indices (Gauge C,n) by A1, A2, A5, MATRIX_1:37;
A11: k >= 1 by A1, XXREAL_0:2;
then [k,i] in Indices (Gauge C,n) by A1, A2, MATRIX_1:37;
then consider k1 being Element of NAT such that
A12: ( j <= k1 & k1 <= k ) and
A13: ((Gauge C,n) * k1,i) `1 = inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n)))) by A1, A6, A8, A10, JORDAN1F:3;
A14: ( 1 <= k1 & k1 <= width (Gauge C,n) ) by A1, A5, A12, XXREAL_0:2;
then A15: ((Gauge C,n) * k1,i) `2 = ((Gauge C,n) * 1,i) `2 by A2, A5, GOBOARD5:2;
then A16: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| = (Gauge C,n) * k1,i by A13, EUCLID:57;
A17: Lower_Seq C,n is_sequence_on Gauge C,n by JORDAN1G:5;
A18: (Gauge C,n) * j,i in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i) by RLTOPSP1:69;
then A19: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i) meets L~ (Lower_Seq C,n) by A3, XBOOLE_0:3;
[k1,i] in Indices (Gauge C,n) by A2, A5, A14, MATRIX_1:37;
then consider j1 being Element of NAT such that
A20: ( j <= j1 & j1 <= k1 ) and
A21: ((Gauge C,n) * j1,i) `1 = sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)))) by A10, A12, A16, A17, A19, JORDAN1F:4;
A22: ( 1 <= j1 & j1 <= width (Gauge C,n) ) by A1, A14, A20, XXREAL_0:2;
then A23: ((Gauge C,n) * j1,i) `2 = ((Gauge C,n) * 1,i) `2 by A2, A5, GOBOARD5:2;
then A24: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| = (Gauge C,n) * j1,i by A21, EUCLID:57;
take j1 ; :: thesis: ex k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )

take k1 ; :: thesis: ( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )
thus ( j <= j1 & j1 <= k1 & k1 <= k ) by A12, A20; :: thesis: ( (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} )
A25: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A2, A5, A14, A16, A20, A22, A24, SPRECT_3:25;
set X = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A3, A18, PSCOMP_1:64, XBOOLE_0:def 4;
consider pp being set such that
A26: pp in E-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A26;
A27: pp in (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) by A26, XBOOLE_0:def 4;
then A28: pp in L~ (Lower_Seq C,n) by XBOOLE_0:def 4;
A29: pp in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i) by A27, XBOOLE_0:def 4;
A30: ((Gauge C,n) * j,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A5, A9, A15, A16, GOBOARD5:2;
then LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| is horizontal by SPPOL_1:36;
then A31: pp `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A15, A16, A23, A24, A29, SPPOL_1:63;
|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 = E-bound ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n))) by A16, A21, A24, SPRECT_1:51
.= (E-min ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)))) `1 by EUCLID:56
.= pp `1 by A26, PSCOMP_1:108 ;
then A32: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in L~ (Lower_Seq C,n) by A28, A31, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| )
proof
let x be set ; :: thesis: ( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| )
thus ( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) implies x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| ) :: thesis: ( x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| implies x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) )
proof
assume A33: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) ; :: thesis: x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A34: pp in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A33, XBOOLE_0:def 4;
then A35: pp `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A15, A16, A23, A24, GOBOARD7:6;
A36: pp `1 >= |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A25, A34, TOPREAL1:9;
reconsider EE = (LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) as compact Subset of (TOP-REAL 2) by PSCOMP_1:64;
reconsider E0 = proj1 .: EE as compact Subset of REAL by Th4;
A37: ((Gauge C,n) * j,i) `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A5, A9, A23, A24, GOBOARD5:2;
((Gauge C,n) * j,i) `1 <= |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A2, A5, A20, A22, A24, SPRECT_3:25;
then A38: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,((Gauge C,n) * j,i) by A15, A16, A23, A24, A25, A37, GOBOARD7:9;
|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by RLTOPSP1:69;
then A39: LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| c= LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A38, TOPREAL1:12;
E0 is bounded by RCOMP_1:28;
then A40: E0 is bounded_above by XXREAL_2:def 11;
pp in L~ (Lower_Seq C,n) by A33, XBOOLE_0:def 4;
then pp in EE by A34, A39, XBOOLE_0:def 4;
then proj1 . pp in E0 by FUNCT_2:43;
then pp `1 in E0 by PSCOMP_1:def 28;
then |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 >= pp `1 by A21, A24, A40, SEQ_4:def 4;
then pp `1 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A36, XXREAL_0:1;
hence x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A35, TOPREAL3:11; :: thesis: verum
end;
assume A41: x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| ; :: thesis: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))
then x in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by RLTOPSP1:69;
hence x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) by A32, A41, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * j1,i)} by A16, A24, TARSKI:def 1; :: thesis: (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)}
set X = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A4, A7, PSCOMP_1:64, XBOOLE_0:def 4;
consider pp being set such that
A42: pp in W-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A42;
A43: pp in (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n)) by A42, XBOOLE_0:def 4;
then A44: pp in L~ (Upper_Seq C,n) by XBOOLE_0:def 4;
A45: pp in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A43, XBOOLE_0:def 4;
((Gauge C,n) * j,i) `2 = ((Gauge C,n) * 1,i) `2 by A1, A2, A5, A9, GOBOARD5:2
.= ((Gauge C,n) * k,i) `2 by A1, A2, A11, GOBOARD5:2 ;
then LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) is horizontal by SPPOL_1:36;
then A46: pp `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A30, A45, SPPOL_1:63;
|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 = W-bound ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))) by A13, A16, SPRECT_1:48
.= (W-min ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n)))) `1 by EUCLID:56
.= pp `1 by A42, PSCOMP_1:88 ;
then A47: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in L~ (Upper_Seq C,n) by A44, A46, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) iff x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| )
proof
let x be set ; :: thesis: ( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) iff x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| )
thus ( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) implies x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| ) :: thesis: ( x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| implies x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) )
proof
assume A48: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) ; :: thesis: x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A49: pp in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A48, XBOOLE_0:def 4;
then A50: pp `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A15, A16, A23, A24, GOBOARD7:6;
A51: pp `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A25, A49, TOPREAL1:9;
reconsider EE = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n)) as compact Subset of (TOP-REAL 2) by PSCOMP_1:64;
reconsider E0 = proj1 .: EE as compact Subset of REAL by Th4;
A52: ((Gauge C,n) * j,i) `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A5, A9, A23, A24, GOBOARD5:2;
A53: ((Gauge C,n) * k,i) `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A11, A23, A24, GOBOARD5:2;
A54: ((Gauge C,n) * j,i) `1 <= |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A2, A5, A20, A22, A24, SPRECT_3:25;
j1 <= k by A12, A20, XXREAL_0:2;
then |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= ((Gauge C,n) * k,i) `1 by A1, A2, A22, A24, SPRECT_3:25;
then A55: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A52, A53, A54, GOBOARD7:9;
A56: ((Gauge C,n) * j,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A5, A9, A15, A16, GOBOARD5:2;
A57: ((Gauge C,n) * k,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A2, A11, A15, A16, GOBOARD5:2;
A58: ((Gauge C,n) * j,i) `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A2, A5, A12, A14, A16, SPRECT_3:25;
|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= ((Gauge C,n) * k,i) `1 by A1, A2, A12, A14, A16, SPRECT_3:25;
then |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A56, A57, A58, GOBOARD7:9;
then A59: LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| c= LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A55, TOPREAL1:12;
E0 is bounded by RCOMP_1:28;
then A60: E0 is bounded_below by XXREAL_2:def 11;
pp in L~ (Upper_Seq C,n) by A48, XBOOLE_0:def 4;
then pp in EE by A49, A59, XBOOLE_0:def 4;
then proj1 . pp in E0 by FUNCT_2:43;
then pp `1 in E0 by PSCOMP_1:def 28;
then |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= pp `1 by A13, A16, A60, SEQ_4:def 5;
then pp `1 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A51, XXREAL_0:1;
hence x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A50, TOPREAL3:11; :: thesis: verum
end;
assume A61: x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| ; :: thesis: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))
then x in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by RLTOPSP1:69;
hence x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,|[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) by A47, A61, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * k1,i)} by A16, A24, TARSKI:def 1; :: thesis: verum