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 <= i & i <= len (Gauge C,n) & 1 <= j & j <= k & k <= width (Gauge C,n) & (Gauge C,n) * i,j in L~ (Lower_Seq C,n) & (Gauge C,n) * i,k 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) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} )

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 <= i & i <= len (Gauge C,n) & 1 <= j & j <= k & k <= width (Gauge C,n) & (Gauge C,n) * i,j in L~ (Lower_Seq C,n) & (Gauge C,n) * i,k 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) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} )

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

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

set G = Gauge C,n;
A8: j <= width (Gauge C,n) by A4, A5, XXREAL_0:2;
then A9: [i,j] in Indices (Gauge C,n) by A1, A2, A3, MATRIX_1:37;
set s = ((Gauge C,n) * i,1) `1 ;
set e = (Gauge C,n) * i,k;
set f = (Gauge C,n) * i,j;
set w1 = lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n))));
A10: (Gauge C,n) * i,k in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by RLTOPSP1:69;
then A11: LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) meets L~ (Upper_Seq C,n) by A7, XBOOLE_0:3;
A12: k >= 1 by A3, A4, XXREAL_0:2;
then [i,k] in Indices (Gauge C,n) by A1, A2, A5, MATRIX_1:37;
then consider k1 being Element of NAT such that
A13: j <= k1 and
A14: k1 <= k and
A15: ((Gauge C,n) * i,k1) `2 = lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))) by A4, A11, A9, JORDAN1F:1, JORDAN1G:4;
A16: k1 <= width (Gauge C,n) by A5, A14, XXREAL_0:2;
A17: (Gauge C,n) * i,j in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1) by RLTOPSP1:69;
then A18: LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1) meets L~ (Lower_Seq C,n) by A6, XBOOLE_0:3;
set X = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A6, A17, XBOOLE_0:def 4;
consider pp being set such that
A19: pp in N-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A19;
A20: pp in (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) by A19, XBOOLE_0:def 4;
then A21: pp in L~ (Lower_Seq C,n) by XBOOLE_0:def 4;
set p = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|;
set w2 = upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n))));
set q = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|;
A22: pp in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1) by A20, XBOOLE_0:def 4;
A23: 1 <= k1 by A3, A13, XXREAL_0:2;
then A24: ((Gauge C,n) * i,k1) `1 = ((Gauge C,n) * i,1) `1 by A1, A2, A16, GOBOARD5:3;
then A25: |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| = (Gauge C,n) * i,k1 by A15, EUCLID:57;
[i,k1] in Indices (Gauge C,n) by A1, A2, A23, A16, MATRIX_1:37;
then consider j1 being Element of NAT such that
A26: j <= j1 and
A27: j1 <= k1 and
A28: ((Gauge C,n) * i,j1) `2 = upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))) by A9, A13, A25, A18, JORDAN1F:2, JORDAN1G:5;
take j1 ; :: thesis: ex k1 being Element of NAT st
( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} )

take k1 ; :: thesis: ( j <= j1 & j1 <= k1 & k1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} )
thus ( j <= j1 & j1 <= k1 & k1 <= k ) by A14, A26, A27; :: thesis: ( (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} )
A29: j1 <= width (Gauge C,n) by A16, A27, XXREAL_0:2;
A30: 1 <= j1 by A3, A26, XXREAL_0:2;
then A31: ((Gauge C,n) * i,j1) `1 = ((Gauge C,n) * i,1) `1 by A1, A2, A29, GOBOARD5:3;
then A32: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| = (Gauge C,n) * i,j1 by A28, EUCLID:57;
then A33: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 <= |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 by A1, A2, A16, A25, A27, A30, SPRECT_3:24;
A34: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 = N-bound ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n))) by A25, A28, A32, SPRECT_1:50
.= (N-min ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)))) `2 by EUCLID:56
.= pp `2 by A19, PSCOMP_1:98 ;
A35: ((Gauge C,n) * i,j) `1 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `1 by A1, A2, A3, A8, A24, A25, GOBOARD5:3;
then LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| is vertical by SPPOL_1:37;
then pp `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `1 by A24, A25, A31, A32, A22, SPPOL_1:64;
then A36: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| in L~ (Lower_Seq C,n) by A21, A34, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| )
proof
let x be set ; :: thesis: ( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| )
thus ( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) implies x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| ) :: thesis: ( x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| implies x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) )
proof
reconsider EE = (LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) as compact Subset of (TOP-REAL 2) ;
reconsider E0 = proj2 .: EE as compact Subset of REAL by JCT_MISC:24;
A37: |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| in LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| by RLTOPSP1:69;
A38: ((Gauge C,n) * i,j) `2 <= |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 by A1, A2, A3, A26, A29, A32, SPRECT_3:24;
((Gauge C,n) * i,j) `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `1 by A1, A2, A3, A8, A31, A32, GOBOARD5:3;
then |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| in LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,((Gauge C,n) * i,j) by A24, A25, A31, A32, A33, A38, GOBOARD7:8;
then A39: LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| c= LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| by A37, TOPREAL1:12;
assume A40: x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) ; :: thesis: x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A41: pp in LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| by A40, XBOOLE_0:def 4;
then A42: pp `2 >= |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 by A33, TOPREAL1:10;
pp in L~ (Lower_Seq C,n) by A40, XBOOLE_0:def 4;
then pp in EE by A41, A39, XBOOLE_0:def 4;
then proj2 . pp in E0 by FUNCT_2:43;
then A43: pp `2 in E0 by PSCOMP_1:def 29;
E0 is bounded by RCOMP_1:28;
then E0 is bounded_above by XXREAL_2:def 11;
then |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 >= pp `2 by A28, A32, A43, SEQ_4:def 4;
then A44: pp `2 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 by A42, XXREAL_0:1;
pp `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `1 by A24, A25, A31, A32, A41, GOBOARD7:5;
hence x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| by A44, TOPREAL3:11; :: thesis: verum
end;
assume A45: x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| ; :: thesis: x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n))
then x in LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| by RLTOPSP1:69;
hence x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) by A36, A45, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} by A25, A32, TARSKI:def 1; :: thesis: (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)}
set X = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n));
reconsider X1 = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A7, A10, XBOOLE_0:def 4;
consider pp being set such that
A46: pp in S-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A46;
A47: pp in (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)) by A46, XBOOLE_0:def 4;
then A48: pp in L~ (Upper_Seq C,n) by XBOOLE_0:def 4;
((Gauge C,n) * i,j) `1 = ((Gauge C,n) * i,1) `1 by A1, A2, A3, A8, GOBOARD5:3
.= ((Gauge C,n) * i,k) `1 by A1, A2, A5, A12, GOBOARD5:3 ;
then A49: LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) is vertical by SPPOL_1:37;
pp in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A47, XBOOLE_0:def 4;
then A50: pp `1 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `1 by A35, A49, SPPOL_1:64;
|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 = S-bound ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n))) by A15, A25, SPRECT_1:49
.= (S-min ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))) `2 by EUCLID:56
.= pp `2 by A46, PSCOMP_1:118 ;
then A51: |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| in L~ (Upper_Seq C,n) by A48, A50, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| )
proof
let x be set ; :: thesis: ( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| )
thus ( x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) implies x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| ) :: thesis: ( x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| implies x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) )
proof
A52: |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 <= ((Gauge C,n) * i,k) `2 by A1, A2, A5, A14, A23, A25, SPRECT_3:24;
A53: ((Gauge C,n) * i,j) `2 <= |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 by A1, A2, A3, A13, A16, A25, SPRECT_3:24;
A54: ((Gauge C,n) * i,k) `1 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `1 by A1, A2, A5, A12, A24, A25, GOBOARD5:3;
((Gauge C,n) * i,j) `1 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `1 by A1, A2, A3, A8, A24, A25, GOBOARD5:3;
then A55: |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A54, A53, A52, GOBOARD7:8;
A56: ((Gauge C,n) * i,k) `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `1 by A1, A2, A5, A12, A31, A32, GOBOARD5:3;
j1 <= k by A14, A27, XXREAL_0:2;
then A57: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 <= ((Gauge C,n) * i,k) `2 by A1, A2, A5, A30, A32, SPRECT_3:24;
A58: ((Gauge C,n) * i,j) `2 <= |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `2 by A1, A2, A3, A26, A29, A32, SPRECT_3:24;
((Gauge C,n) * i,j) `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| `1 by A1, A2, A3, A8, A31, A32, GOBOARD5:3;
then |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A56, A58, A57, GOBOARD7:8;
then A59: LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| c= LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A55, TOPREAL1:12;
reconsider EE = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)) as compact Subset of (TOP-REAL 2) ;
reconsider E0 = proj2 .: EE as compact Subset of REAL by JCT_MISC:24;
assume A60: x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) ; :: thesis: x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A61: pp in LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| by A60, XBOOLE_0:def 4;
then A62: pp `2 <= |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 by A33, TOPREAL1:10;
pp in L~ (Upper_Seq C,n) by A60, XBOOLE_0:def 4;
then pp in EE by A61, A59, XBOOLE_0:def 4;
then proj2 . pp in E0 by FUNCT_2:43;
then A63: pp `2 in E0 by PSCOMP_1:def 29;
E0 is bounded by RCOMP_1:28;
then E0 is bounded_below by XXREAL_2:def 11;
then |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 <= pp `2 by A15, A25, A63, SEQ_4:def 5;
then A64: pp `2 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `2 by A62, XXREAL_0:1;
pp `1 = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| `1 by A24, A25, A31, A32, A61, GOBOARD7:5;
hence x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| by A64, TOPREAL3:11; :: thesis: verum
end;
assume A65: x = |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]| ; :: thesis: x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n))
then x in LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]| by RLTOPSP1:69;
hence x in (LSeg |[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|,|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),|[(((Gauge C,n) * i,1) `1 ),(lower_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Upper_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Upper_Seq C,n)) by A51, A65, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k1)) /\ (L~ (Upper_Seq C,n)) = {((Gauge C,n) * i,k1)} by A25, A32, TARSKI:def 1; :: thesis: verum