let m, n, j be Element of NAT ; :: thesis: for E being compact non horizontal non vertical Subset of (TOP-REAL 2) st 1 <= m & m <= n & 1 <= j & j <= width (Gauge E,n) holds
LSeg ((Gauge E,n) * (Center (Gauge E,n)),1),((Gauge E,n) * (Center (Gauge E,n)),j) c= LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j)
let E be compact non horizontal non vertical Subset of (TOP-REAL 2); :: thesis: ( 1 <= m & m <= n & 1 <= j & j <= width (Gauge E,n) implies LSeg ((Gauge E,n) * (Center (Gauge E,n)),1),((Gauge E,n) * (Center (Gauge E,n)),j) c= LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) )
set a = N-bound E;
set s = S-bound E;
set w = W-bound E;
set e = E-bound E;
set G = Gauge E,n;
set M = Gauge E,m;
set sn = Center (Gauge E,n);
set sm = Center (Gauge E,m);
assume that
A1: 1 <= m and
A2: m <= n and
A3: 1 <= j and
A4: j <= width (Gauge E,n) ; :: thesis: LSeg ((Gauge E,n) * (Center (Gauge E,n)),1),((Gauge E,n) * (Center (Gauge E,n)),j) c= LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j)

now

A5: 0 < (N-bound E) - (S-bound E) by SPRECT_1:34, XREAL_1:52;
then A6: (S-bound E) - (((N-bound E) - (S-bound E)) / (2 |^ m)) <= (S-bound E) - 0 by XREAL_1:15;
A7: ((N-bound E) - (S-bound E)) / (2 |^ n) <= ((N-bound E) - (S-bound E)) / (2 |^ m) by A2, A5, Lm7;
A8: 1 <= len (Gauge E,m) by GOBRD11:34;
then [(Center (Gauge E,m)),1] in Indices (Gauge E,m) by Lm4;
then A9: ((Gauge E,m) * (Center (Gauge E,m)),1) `2 = (S-bound E) - (((N-bound E) - (S-bound E)) / (2 |^ m)) by Lm11;
let t be Element of NAT ; :: thesis: ( 1 <= t & t <= j implies (Gauge E,n) * (Center (Gauge E,n)),t in LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) )
assume that
A10: 1 <= t and
A11: t <= j ; :: thesis: (Gauge E,n) * (Center (Gauge E,n)),t in LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j)
( 1 <= Center (Gauge E,n) & Center (Gauge E,n) <= len (Gauge E,n) ) by Lm3;
then A12: ((Gauge E,n) * (Center (Gauge E,n)),t) `2 <= ((Gauge E,n) * (Center (Gauge E,n)),j) `2 by A4, A10, A11, SPRECT_3:24;
A13: len (Gauge E,n) = width (Gauge E,n) by JORDAN8:def 1;
then A14: t <= len (Gauge E,n) by A4, A11, XXREAL_0:2;
then A15: ((Gauge E,m) * (Center (Gauge E,m)),1) `1 = ((Gauge E,n) * (Center (Gauge E,n)),t) `1 by A1, A2, A10, A8, Th57;
A16: [(Center (Gauge E,n)),t] in Indices (Gauge E,n) by A10, A14, Lm4;
then A17: ((Gauge E,n) * (Center (Gauge E,n)),t) `2 = |[((W-bound E) + ((((E-bound E) - (W-bound E)) / (2 |^ n)) * ((Center (Gauge E,n)) - 2))),((S-bound E) + ((((N-bound E) - (S-bound E)) / (2 |^ n)) * (t - 2)))]| `2 by JORDAN8:def 1
.= (S-bound E) + ((((N-bound E) - (S-bound E)) / (2 |^ n)) * (t - 2)) by EUCLID:56 ;

A18: now

per cases ( t = 1 or t > 1 ) by A10, XXREAL_0:1;

suppose t = 1 ; :: thesis: ((Gauge E,m) * (Center (Gauge E,m)),1) `2 <= ((Gauge E,n) * (Center (Gauge E,n)),t) `2

then ((Gauge E,n) * (Center (Gauge E,n)),t) `2 = (S-bound E) - (((N-bound E) - (S-bound E)) / (2 |^ n)) by A16, Lm11;
hence ((Gauge E,m) * (Center (Gauge E,m)),1) `2 <= ((Gauge E,n) * (Center (Gauge E,n)),t) `2 by A7, A9, XREAL_1:15; :: thesis: verum

end;

suppose t > 1 ; :: thesis: ((Gauge E,m) * (Center (Gauge E,m)),1) `2 <= ((Gauge E,n) * (Center (Gauge E,n)),t) `2

then t >= 1 + 1 by NAT_1:13;
then t - 2 >= 2 - 2 by XREAL_1:11;
then (S-bound E) + 0 <= (S-bound E) + ((((N-bound E) - (S-bound E)) / (2 |^ n)) * (t - 2)) by A5, XREAL_1:8;
hence ((Gauge E,m) * (Center (Gauge E,m)),1) `2 <= ((Gauge E,n) * (Center (Gauge E,n)),t) `2 by A17, A6, A9, XXREAL_0:2; :: thesis: verum

end;

end;

end;

((Gauge E,n) * (Center (Gauge E,n)),t) `1 = ((Gauge E,n) * (Center (Gauge E,n)),j) `1 by A1, A2, A3, A4, A10, A13, A14, Th57;
hence (Gauge E,n) * (Center (Gauge E,n)),t in LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) by A15, A18, A12, GOBOARD7:8; :: thesis: verum

end;

then ( (Gauge E,n) * (Center (Gauge E,n)),1 in LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) & (Gauge E,n) * (Center (Gauge E,n)),j in LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) ) by A3;
hence LSeg ((Gauge E,n) * (Center (Gauge E,n)),1),((Gauge E,n) * (Center (Gauge E,n)),j) c= LSeg ((Gauge E,m) * (Center (Gauge E,m)),1),((Gauge E,n) * (Center (Gauge E,n)),j) by TOPREAL1:12; :: thesis: verum