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

set G = Gauge C,n;
A7: k >= 1 by A1, A2, XXREAL_0:2;
then A8: [k,i] in Indices (Gauge C,n) by A3, A4, A5, MATRIX_1:37;
set X = (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n));
A9: (Gauge C,n) * k,i in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by RLTOPSP1:69;
then 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 A6, XBOOLE_0:def 4;
A10: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) meets L~ (Lower_Seq C,n) by A6, A9, XBOOLE_0:3;
set s = ((Gauge C,n) * 1,i) `2 ;
set e = (Gauge C,n) * k,i;
set f = (Gauge C,n) * j,i;
set w1 = lower_bound (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))));
A11: len (Gauge C,n) = width (Gauge C,n) by JORDAN8:def 1;
then A12: j <= width (Gauge C,n) by A2, A3, XXREAL_0:2;
then [j,i] in Indices (Gauge C,n) by A1, A4, A5, A11, MATRIX_1:37;
then consider k1 being Element of NAT such that
A13: j <= k1 and
A14: k1 <= k and
A15: ((Gauge C,n) * k1,i) `1 = lower_bound (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)))) by A2, A10, A8, JORDAN1F:3, JORDAN1G:5;
set p = |[(lower_bound (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]|;
A16: k1 <= width (Gauge C,n) by A3, A11, A14, XXREAL_0:2;
((Gauge C,n) * j,i) `2 = ((Gauge C,n) * 1,i) `2 by A1, A4, A5, A11, A12, GOBOARD5:2
.= ((Gauge C,n) * k,i) `2 by A3, A4, A5, A7, GOBOARD5:2 ;
then A17: LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) is horizontal by SPPOL_1:36;
take k1 ; :: thesis: ( j <= k1 & k1 <= k & (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} )
thus ( j <= k1 & k1 <= k ) by A13, A14; :: thesis: (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)}
consider pp being set such that
A18: pp in W-most X1 by XBOOLE_0:def 1;
A19: 1 <= k1 by A1, A13, XXREAL_0:2;
then A20: ((Gauge C,n) * k1,i) `2 = ((Gauge C,n) * 1,i) `2 by A4, A5, A11, A16, GOBOARD5:2;
then A21: |[(lower_bound (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 A15, EUCLID:57;
then A22: ((Gauge C,n) * j,i) `1 <= |[(lower_bound (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, A11, A13, A16, SPRECT_3:25;
A23: ((Gauge C,n) * j,i) `2 = |[(lower_bound (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, A11, A12, A20, A21, GOBOARD5:2;
reconsider pp = pp as Point of (TOP-REAL 2) by A18;
A24: pp in (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n)) by A18, XBOOLE_0:def 4;
then A25: pp in L~ (Lower_Seq C,n) by XBOOLE_0:def 4;
A26: |[(lower_bound (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 A15, A21, 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 A18, PSCOMP_1:88 ;
pp in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A24, XBOOLE_0:def 4;
then pp `2 = |[(lower_bound (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 A23, A17, SPPOL_1:63;
then A27: |[(lower_bound (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 A25, A26, TOPREAL3:11;
for x being set holds
( x in (LSeg |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) iff x = |[(lower_bound (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 |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) iff x = |[(lower_bound (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 |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) implies x = |[(lower_bound (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 = |[(lower_bound (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 |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) )
proof
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) ;
assume A28: x in (LSeg |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) ; :: thesis: x = |[(lower_bound (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) ;
A29: pp in LSeg |[(lower_bound (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 A28, XBOOLE_0:def 4;
then A30: pp `1 <= |[(lower_bound (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 A22, TOPREAL1:9;
A31: |[(lower_bound (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, A14, A19, A21, SPRECT_3:25;
A32: ((Gauge C,n) * j,i) `1 <= |[(lower_bound (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, A11, A13, A16, A21, SPRECT_3:25;
A33: ((Gauge C,n) * k,i) `2 = |[(lower_bound (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, A7, A20, A21, GOBOARD5:2;
reconsider E0 = proj1 .: EE as compact Subset of REAL by Th4;
A34: (Gauge C,n) * j,i in LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by RLTOPSP1:69;
((Gauge C,n) * j,i) `2 = |[(lower_bound (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, A11, A12, A20, A21, GOBOARD5:2;
then |[(lower_bound (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 A33, A32, A31, GOBOARD7:9;
then A35: LSeg |[(lower_bound (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) c= LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i) by A34, TOPREAL1:12;
pp in L~ (Lower_Seq C,n) by A28, XBOOLE_0:def 4;
then pp in EE by A29, A35, XBOOLE_0:def 4;
then proj1 . pp in E0 by FUNCT_2:43;
then A36: 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 |[(lower_bound (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 A15, A21, A36, SEQ_4:def 5;
then A37: pp `1 = |[(lower_bound (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 A30, XXREAL_0:1;
pp `2 = |[(lower_bound (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 A23, A29, GOBOARD7:6;
hence x = |[(lower_bound (proj1 .: ((LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k,i)) /\ (L~ (Lower_Seq C,n))))),(((Gauge C,n) * 1,i) `2 )]| by A37, TOPREAL3:11; :: thesis: verum
end;
assume A38: x = |[(lower_bound (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 |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n))
then x in LSeg |[(lower_bound (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 RLTOPSP1:69;
hence x in (LSeg |[(lower_bound (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)) /\ (L~ (Lower_Seq C,n)) by A27, A38, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * j,i),((Gauge C,n) * k1,i)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * k1,i)} by A21, TARSKI:def 1; :: thesis: verum