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~ (Upper_Seq C,n) & (Gauge C,n) * k,i in L~ (Lower_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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_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~ (Upper_Seq C,n) & (Gauge C,n) * k,i in L~ (Lower_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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_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~ (Upper_Seq C,n) & (Gauge C,n) * k,i in L~ (Lower_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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} ) )

assume that
A1: 1 <= j and
A2: j <= k and
A3: k <= len (Gauge C,n) and
A4: 1 <= i and
A5: i <= width (Gauge C,n) and
A6: (Gauge C,n) * j,i in L~ (Upper_Seq C,n) and
A7: (Gauge C,n) * k,i in L~ (Lower_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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} )

set G = Gauge C,n;
A8: len (Gauge C,n) = width (Gauge C,n) by JORDAN8:def 1;
then A9: j <= width (Gauge C,n) by A2, A3, XXREAL_0:2;
then A10: [j,i] in Indices (Gauge C,n) by A1, A4, A5, A8, MATRIX_1:37;
set s = ((Gauge C,n) * 1,i) `2 ;
set e = (Gauge C,n) * k,i;
set f = (Gauge C,n) * j,i;
set w1 = inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))));
A11: (Gauge C,n) * k,i in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by RLTOPSP1:69;
then A12: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) meets L~ (Lower_Seq C,n) by A7, XBOOLE_0:3;
A13: k >= 1 by A1, A2, XXREAL_0:2;
then [k,i] in Indices (Gauge C,n) by A3, A4, A5, MATRIX_1:37;
then consider k1 being Element of NAT such that
A14: j <= k1 and
A15: k1 <= k and
A16: ((Gauge C,n) * k1,i) `1 = inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)))) by A2, A12, A10, JORDAN1F:3, JORDAN1G:5;
A17: k1 <= width (Gauge C,n) by A3, A8, A15, XXREAL_0:2;
set p = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|;
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~ (Upper_Seq C,n) by A6, XBOOLE_0:3;
A20: 1 <= k1 by A1, A14, XXREAL_0:2;
then A21: ((Gauge C,n) * k1,i) `2 = ((Gauge C,n) * 1,i) `2 by A4, A5, A8, A17, GOBOARD5:2;
then A22: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| = (Gauge C,n) * k1,i by A16, EUCLID:57;
((Gauge C,n) * j,i) `2 = ((Gauge C,n) * 1,i) `2 by A1, A4, A5, A8, A9, GOBOARD5:2
.= ((Gauge C,n) * k,i) `2 by A3, A4, A5, A13, GOBOARD5:2 ;
then A23: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) is horizontal by SPPOL_1:36;
set X = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A6, A18, PSCOMP_1:64, XBOOLE_0:def 4;
consider pp being set such that
A24: pp in E-most X1 by XBOOLE_0:def 1;
[k1,i] in Indices (Gauge C,n) by A4, A5, A8, A20, A17, MATRIX_1:37;
then consider j1 being Element of NAT such that
A25: j <= j1 and
A26: j1 <= k1 and
A27: ((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)))) by A10, A14, A22, A19, JORDAN1F:4, JORDAN1G:4;
A28: j1 <= width (Gauge C,n) by A17, A26, XXREAL_0:2;
reconsider pp = pp as Point of (TOP-REAL 2) by A24;
A29: pp in (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) by A24, XBOOLE_0:def 4;
then A30: pp in L~ (Upper_Seq C,n) by XBOOLE_0:def 4;
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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_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~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} )
thus ( j <= j1 & j1 <= k1 & k1 <= k ) by A15, A25, A26; :: thesis: ( (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * j1,i)} & (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} )
A31: pp in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i) by A29, XBOOLE_0:def 4;
A32: 1 <= j1 by A1, A25, XXREAL_0:2;
then A33: ((Gauge C,n) * j1,i) `2 = ((Gauge C,n) * 1,i) `2 by A4, A5, A8, A28, GOBOARD5:2;
then A34: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| = (Gauge C,n) * j1,i by A27, EUCLID:57;
then A35: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A4, A5, A8, A17, A22, A26, A32, SPRECT_3:25;
A36: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 = E-bound ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n))) by A22, A27, A34, SPRECT_1:51
.= (E-min ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Upper_Seq C,n)))) `1 by EUCLID:56
.= pp `1 by A24, PSCOMP_1:108 ;
A37: ((Gauge C,n) * j,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A4, A5, A8, A9, A21, A22, GOBOARD5:2;
then LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| is horizontal by SPPOL_1:36;
then pp `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A21, A22, A33, A34, A31, SPPOL_1:63;
then A38: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in L~ (Upper_Seq C,n) by A30, A36, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) )
proof
reconsider EE = (LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) as compact Subset of (TOP-REAL 2) by PSCOMP_1:64;
assume A39: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A40: pp in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A39, XBOOLE_0:def 4;
then A41: pp `1 >= |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A35, TOPREAL1:9;
A42: ((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A4, A5, A8, A25, A28, A34, SPRECT_3:25;
reconsider E0 = proj1 .: EE as compact Subset of REAL by Th4;
A43: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by RLTOPSP1:69;
((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A4, A5, A8, A9, A33, A34, GOBOARD5:2;
then |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|,((Gauge C,n) * j,i) by A21, A22, A33, A34, A35, A42, GOBOARD7:9;
then A44: LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A43, TOPREAL1:12;
pp in L~ (Upper_Seq C,n) by A39, XBOOLE_0:def 4;
then pp in EE by A40, A44, XBOOLE_0:def 4;
then proj1 . pp in E0 by FUNCT_2:43;
then A45: pp `1 in E0 by PSCOMP_1:def 28;
E0 is bounded by RCOMP_1:28;
then E0 is bounded_above by XXREAL_2:def 11;
then |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 >= pp `1 by A27, A34, A45, SEQ_4:def 4;
then A46: pp `1 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A41, XXREAL_0:1;
pp `2 = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A21, A22, A33, A34, A40, GOBOARD7:6;
hence x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A46, TOPREAL3:11; :: thesis: verum
end;
assume A47: x = |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n)) by A38, A47, 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) * j1,i)} by A22, A34, TARSKI:def 1; :: thesis: (LSeg ((Gauge C,n) * j1,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)}
set X = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A7, A11, PSCOMP_1:64, XBOOLE_0:def 4;
consider pp being set such that
A48: pp in W-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A48;
A49: pp in (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)) by A48, XBOOLE_0:def 4;
then A50: pp in L~ (Lower_Seq C,n) by XBOOLE_0:def 4;
pp in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A49, XBOOLE_0:def 4;
then A51: pp `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A37, A23, SPPOL_1:63;
|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 = W-bound ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))) by A16, A22, SPRECT_1:48
.= (W-min ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)))) `1 by EUCLID:56
.= pp `1 by A48, PSCOMP_1:88 ;
then A52: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in L~ (Lower_Seq C,n) by A50, A51, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) implies x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) )
proof
j1 <= k by A15, A26, XXREAL_0:2;
then A53: |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= ((Gauge C,n) * k,i) `1 by A3, A4, A5, A32, A34, SPRECT_3:25;
A54: ((Gauge C,n) * k,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A3, A4, A5, A13, A21, A22, GOBOARD5:2;
A55: ((Gauge C,n) * j,i) `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A4, A5, A8, A14, A17, A22, SPRECT_3:25;
A56: ((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A1, A4, A5, A8, A25, A28, A34, SPRECT_3:25;
A57: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= ((Gauge C,n) * k,i) `1 by A3, A4, A5, A15, A20, A22, SPRECT_3:25;
((Gauge C,n) * j,i) `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A4, A5, A8, A9, A21, A22, GOBOARD5:2;
then A58: |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A54, A55, A57, GOBOARD7:9;
A59: ((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A3, A4, A5, A13, A33, A34, GOBOARD5:2;
((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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A1, A4, A5, A8, A9, A33, A34, GOBOARD5:2;
then |[(sup (proj1 .: ((LSeg ((Gauge C,n) * j,i),|[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A59, A56, A53, GOBOARD7:9;
then A60: LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| c= LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A58, TOPREAL1:12;
reconsider EE = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (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;
assume A61: x in (LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) ; :: thesis: x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A62: pp in LSeg |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A61, XBOOLE_0:def 4;
then A63: pp `1 <= |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A35, TOPREAL1:9;
pp in L~ (Lower_Seq C,n) by A61, XBOOLE_0:def 4;
then pp in EE by A62, A60, XBOOLE_0:def 4;
then proj1 . pp in E0 by FUNCT_2:43;
then A64: pp `1 in E0 by PSCOMP_1:def 28;
E0 is bounded by RCOMP_1:28;
then E0 is bounded_below by XXREAL_2:def 11;
then |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 <= pp `1 by A16, A22, A64, SEQ_4:def 5;
then A65: pp `1 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `1 by A63, XXREAL_0:1;
pp `2 = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| `2 by A21, A22, A33, A34, A62, GOBOARD7:6;
hence x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A65, TOPREAL3:11; :: thesis: verum
end;
assume A66: x = |[(inf (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_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~ (Lower_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~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Upper_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|) /\ (L~ (Lower_Seq C,n)) by A52, A66, 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) * k1,i)} by A22, A34, TARSKI:def 1; :: thesis: verum