let n be Element of NAT ; :: thesis: for C being connected compact non horizontal non vertical Subset of (TOP-REAL 2)
for p being Point of (TOP-REAL 2) st p in L~ (Lower_Seq (C,n)) & p `1 = W-bound (L~ (Cage (C,n))) holds
p = W-min (L~ (Cage (C,n)))

let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); :: thesis: for p being Point of (TOP-REAL 2) st p in L~ (Lower_Seq (C,n)) & p `1 = W-bound (L~ (Cage (C,n))) holds
p = W-min (L~ (Cage (C,n)))

let p be Point of (TOP-REAL 2); :: thesis: ( p in L~ (Lower_Seq (C,n)) & p `1 = W-bound (L~ (Cage (C,n))) implies p = W-min (L~ (Cage (C,n))) )
set Ca = Cage (C,n);
set LS = Lower_Seq (C,n);
set US = Upper_Seq (C,n);
set Emax = E-max (L~ (Cage (C,n)));
set Nmin = N-min (L~ (Cage (C,n)));
set Nmax = N-max (L~ (Cage (C,n)));
set Wmax = W-max (L~ (Cage (C,n)));
set Wmin = W-min (L~ (Cage (C,n)));
set Ebo = E-bound (L~ (Cage (C,n)));
set Sbo = S-bound (L~ (Cage (C,n)));
set Wbo = W-bound (L~ (Cage (C,n)));
set Nbo = N-bound (L~ (Cage (C,n)));
set SW = SW-corner (L~ (Cage (C,n)));
assume that
A1: p in L~ (Lower_Seq (C,n)) and
A2: p `1 = W-bound (L~ (Cage (C,n))) and
A3: p <> W-min (L~ (Cage (C,n))) ; :: thesis: contradiction
A4: (Lower_Seq (C,n)) /. 1 = E-max (L~ (Cage (C,n))) by JORDAN1F:6;
1 in dom (Lower_Seq (C,n)) by FINSEQ_5:6;
then A5: (Lower_Seq (C,n)) . 1 = E-max (L~ (Cage (C,n))) by A4, PARTFUN1:def 8;
E-bound (L~ (Cage (C,n))) <> W-bound (L~ (Cage (C,n))) by SPRECT_1:33;
then p <> (Lower_Seq (C,n)) . 1 by A2, A5, EUCLID:56;
then reconsider g1 = R_Cut ((Lower_Seq (C,n)),p) as being_S-Seq FinSequence of (TOP-REAL 2) by A1, JORDAN3:70;
len g1 in dom g1 by FINSEQ_5:6;
then A6: g1 /. (len g1) = g1 . (len g1) by PARTFUN1:def 8
.= p by A1, JORDAN3:59 ;
reconsider g = Rev g1 as being_S-Seq FinSequence of (TOP-REAL 2) ;
<*p*> is_in_the_area_of Cage (C,n) by A1, JORDAN1E:22, SPRECT_3:63;
then g1 is_in_the_area_of Cage (C,n) by A1, JORDAN1E:22, SPRECT_3:69;
then A7: g is_in_the_area_of Cage (C,n) by SPRECT_3:68;
A8: g /. 1 = g1 /. (len g1) by FINSEQ_5:68;
A9: g /. (len g) = g /. (len g1) by FINSEQ_5:def 3
.= g1 /. 1 by FINSEQ_5:68 ;
(g1 /. 1) `1 = ((Lower_Seq (C,n)) /. 1) `1 by A1, SPRECT_3:39
.= (E-max (L~ (Cage (C,n)))) `1 by JORDAN1F:6
.= E-bound (L~ (Cage (C,n))) by EUCLID:56 ;
then A10: g is_a_h.c._for Cage (C,n) by A2, A7, A8, A9, A6, SPRECT_2:def 2;
A11: (Upper_Seq (C,n)) /. 1 = W-min (L~ (Cage (C,n))) by JORDAN1F:5;
1 in dom (Upper_Seq (C,n)) by FINSEQ_5:6;
then A12: (Upper_Seq (C,n)) . 1 = W-min (L~ (Cage (C,n))) by A11, PARTFUN1:def 8;
A13: L~ g = L~ g1 by SPPOL_2:22;
len (Cage (C,n)) > 4 by GOBOARD7:36;
then A14: rng (Cage (C,n)) c= L~ (Cage (C,n)) by SPPOL_2:18, XXREAL_0:2;
now
per cases ( W-min (L~ (Cage (C,n))) <> SW-corner (L~ (Cage (C,n))) or W-min (L~ (Cage (C,n))) = SW-corner (L~ (Cage (C,n))) ) ;
suppose A15: W-min (L~ (Cage (C,n))) <> SW-corner (L~ (Cage (C,n))) ; :: thesis: contradiction
A16: not SW-corner (L~ (Cage (C,n))) in rng (Cage (C,n))
proof
A17: (SW-corner (L~ (Cage (C,n)))) `1 = W-bound (L~ (Cage (C,n))) by EUCLID:56;
A18: (SW-corner (L~ (Cage (C,n)))) `2 = S-bound (L~ (Cage (C,n))) by EUCLID:56;
then (SW-corner (L~ (Cage (C,n)))) `2 <= N-bound (L~ (Cage (C,n))) by SPRECT_1:24;
then SW-corner (L~ (Cage (C,n))) in { p1 where p1 is Point of (TOP-REAL 2) : ( p1 `1 = W-bound (L~ (Cage (C,n))) & p1 `2 <= N-bound (L~ (Cage (C,n))) & p1 `2 >= S-bound (L~ (Cage (C,n))) ) } by A17, A18;
then A19: SW-corner (L~ (Cage (C,n))) in LSeg ((SW-corner (L~ (Cage (C,n)))),(NW-corner (L~ (Cage (C,n))))) by SPRECT_1:28;
assume SW-corner (L~ (Cage (C,n))) in rng (Cage (C,n)) ; :: thesis: contradiction
then SW-corner (L~ (Cage (C,n))) in (LSeg ((SW-corner (L~ (Cage (C,n)))),(NW-corner (L~ (Cage (C,n)))))) /\ (L~ (Cage (C,n))) by A14, A19, XBOOLE_0:def 4;
then A20: (SW-corner (L~ (Cage (C,n)))) `2 >= (W-min (L~ (Cage (C,n)))) `2 by PSCOMP_1:88;
A21: (W-min (L~ (Cage (C,n)))) `1 = (SW-corner (L~ (Cage (C,n)))) `1 by PSCOMP_1:85;
(W-min (L~ (Cage (C,n)))) `2 >= (SW-corner (L~ (Cage (C,n)))) `2 by PSCOMP_1:87;
then (W-min (L~ (Cage (C,n)))) `2 = (SW-corner (L~ (Cage (C,n)))) `2 by A20, XXREAL_0:1;
hence contradiction by A15, A21, TOPREAL3:11; :: thesis: verum
end;
N-min (L~ (Cage (C,n))) in rng (Upper_Seq (C,n)) by Th7;
then R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) = mid ((Upper_Seq (C,n)),1,((N-min (L~ (Cage (C,n)))) .. (Upper_Seq (C,n)))) by JORDAN1G:57;
then A22: rng (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) c= rng (Upper_Seq (C,n)) by FINSEQ_6:125;
rng (Upper_Seq (C,n)) c= rng (Cage (C,n)) by JORDAN1G:47;
then rng (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) c= rng (Cage (C,n)) by A22, XBOOLE_1:1;
then not SW-corner (L~ (Cage (C,n))) in rng (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A16;
then rng (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) misses {(SW-corner (L~ (Cage (C,n))))} by ZFMISC_1:56;
then rng (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) misses rng <*(SW-corner (L~ (Cage (C,n))))*> by FINSEQ_1:55;
then A23: rng (Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) misses rng <*(SW-corner (L~ (Cage (C,n))))*> by FINSEQ_5:60;
set h1 = (Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) ^ <*(SW-corner (L~ (Cage (C,n))))*>;
A24: <*(SW-corner (L~ (Cage (C,n))))*> is one-to-one by FINSEQ_3:102;
W-max (L~ (Cage (C,n))) in L~ (Cage (C,n)) by SPRECT_1:15;
then A25: N-bound (L~ (Cage (C,n))) >= (W-max (L~ (Cage (C,n)))) `2 by PSCOMP_1:71;
A26: <*(SW-corner (L~ (Cage (C,n))))*> is special ;
A27: N-min (L~ (Cage (C,n))) in L~ (Upper_Seq (C,n)) by Th7;
then <*(N-min (L~ (Cage (C,n))))*> is_in_the_area_of Cage (C,n) by JORDAN1E:21, SPRECT_3:63;
then R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) is_in_the_area_of Cage (C,n) by A27, JORDAN1E:21, SPRECT_3:69;
then A28: Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) is_in_the_area_of Cage (C,n) by SPRECT_3:68;
(W-max (L~ (Cage (C,n)))) `2 > (W-min (L~ (Cage (C,n)))) `2 by SPRECT_2:61;
then A29: N-min (L~ (Cage (C,n))) <> (Upper_Seq (C,n)) . 1 by A12, A25, EUCLID:56;
then reconsider RCutUS = R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) as being_S-Seq FinSequence of (TOP-REAL 2) by A27, JORDAN3:70;
A30: Rev RCutUS is special ;
A31: (Rev RCutUS) /. (len (Rev RCutUS)) = (Rev RCutUS) /. (len RCutUS) by FINSEQ_5:def 3
.= RCutUS /. 1 by FINSEQ_5:68
.= (Upper_Seq (C,n)) /. 1 by A27, SPRECT_3:39
.= W-min (L~ (Cage (C,n))) by JORDAN1F:5 ;
then ((Rev RCutUS) /. (len (Rev RCutUS))) `1 = W-bound (L~ (Cage (C,n))) by EUCLID:56
.= (SW-corner (L~ (Cage (C,n)))) `1 by EUCLID:56
.= (<*(SW-corner (L~ (Cage (C,n))))*> /. 1) `1 by FINSEQ_4:25 ;
then reconsider h1 = (Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) ^ <*(SW-corner (L~ (Cage (C,n))))*> as one-to-one special FinSequence of (TOP-REAL 2) by A23, A24, A26, FINSEQ_3:98, GOBOARD2:13;
set h = Rev h1;
A32: Rev h1 is special by SPPOL_2:42;
<*(SW-corner (L~ (Cage (C,n))))*> is_in_the_area_of Cage (C,n) by SPRECT_2:32;
then h1 is_in_the_area_of Cage (C,n) by A28, SPRECT_2:28;
then A33: Rev h1 is_in_the_area_of Cage (C,n) by SPRECT_3:68;
L~ (Rev h1) = L~ h1 by SPPOL_2:22;
then A34: L~ (Rev h1) = (L~ (Rev RCutUS)) \/ (LSeg (((Rev RCutUS) /. (len (Rev RCutUS))),(SW-corner (L~ (Cage (C,n)))))) by SPPOL_2:19;
A35: (Index ((N-min (L~ (Cage (C,n)))),(Upper_Seq (C,n)))) + 1 >= 0 + 1 by XREAL_1:9;
A36: 2 <= len g by TOPREAL1:def 10;
len h1 = (len (Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))))) + 1 by FINSEQ_2:19
.= (len (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) + 1 by FINSEQ_5:def 3
.= ((Index ((N-min (L~ (Cage (C,n)))),(Upper_Seq (C,n)))) + 1) + 1 by A27, A29, JORDAN3:60 ;
then len h1 >= 1 + 1 by A35, XREAL_1:9;
then A37: len (Rev h1) >= 2 by FINSEQ_5:def 3;
A38: (Rev h1) /. 1 = h1 /. (len h1) by FINSEQ_5:68;
A39: len (Upper_Seq (C,n)) in dom (Upper_Seq (C,n)) by FINSEQ_5:6;
1 in dom (Rev RCutUS) by FINSEQ_5:6;
then h1 /. 1 = (Rev RCutUS) /. 1 by FINSEQ_4:83
.= (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) /. (len (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) by FINSEQ_5:68
.= N-min (L~ (Cage (C,n))) by A27, Th45 ;
then A40: (h1 /. 1) `2 = N-bound (L~ (Cage (C,n))) by EUCLID:56;
A41: (h1 /. (len h1)) `2 = (h1 /. ((len (Rev (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))))) + 1)) `2 by FINSEQ_2:19
.= (SW-corner (L~ (Cage (C,n)))) `2 by FINSEQ_4:82
.= S-bound (L~ (Cage (C,n))) by EUCLID:56 ;
A42: len (Lower_Seq (C,n)) in dom (Lower_Seq (C,n)) by FINSEQ_5:6;
(Rev h1) /. (len (Rev h1)) = (Rev h1) /. (len h1) by FINSEQ_5:def 3
.= h1 /. 1 by FINSEQ_5:68 ;
then Rev h1 is_a_v.c._for Cage (C,n) by A33, A40, A38, A41, SPRECT_2:def 3;
then L~ g meets L~ (Rev h1) by A10, A32, A36, A37, SPRECT_2:33;
then consider x being set such that
A43: x in L~ g and
A44: x in L~ (Rev h1) by XBOOLE_0:3;
reconsider x = x as Point of (TOP-REAL 2) by A43;
A45: L~ RCutUS c= L~ (Upper_Seq (C,n)) by Th7, JORDAN3:76;
A46: L~ g c= L~ (Lower_Seq (C,n)) by A1, A13, JORDAN3:76;
then A47: x in L~ (Lower_Seq (C,n)) by A43;
now
per cases ( x in L~ (Rev RCutUS) or x in LSeg (((Rev RCutUS) /. (len (Rev RCutUS))),(SW-corner (L~ (Cage (C,n))))) ) by A44, A34, XBOOLE_0:def 3;
suppose x in L~ (Rev RCutUS) ; :: thesis: contradiction
then A48: x in L~ RCutUS by SPPOL_2:22;
then x in (L~ (Lower_Seq (C,n))) /\ (L~ (Upper_Seq (C,n))) by A43, A46, A45, XBOOLE_0:def 4;
then A49: x in {(E-max (L~ (Cage (C,n)))),(W-min (L~ (Cage (C,n))))} by JORDAN1E:20;
now
per cases ( x = E-max (L~ (Cage (C,n))) or x = W-min (L~ (Cage (C,n))) ) by A49, TARSKI:def 2;
suppose x = E-max (L~ (Cage (C,n))) ; :: thesis: contradiction
then (Upper_Seq (C,n)) /. (len (Upper_Seq (C,n))) in L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A48, JORDAN1F:7;
then (Upper_Seq (C,n)) . (len (Upper_Seq (C,n))) in L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A39, PARTFUN1:def 8;
then (Upper_Seq (C,n)) . (len (Upper_Seq (C,n))) = N-min (L~ (Cage (C,n))) by A27, Th43;
then (Upper_Seq (C,n)) /. (len (Upper_Seq (C,n))) = N-min (L~ (Cage (C,n))) by A39, PARTFUN1:def 8;
then A50: E-max (L~ (Cage (C,n))) = N-min (L~ (Cage (C,n))) by JORDAN1F:7;
N-max (L~ (Cage (C,n))) in L~ (Cage (C,n)) by SPRECT_1:13;
then A51: E-bound (L~ (Cage (C,n))) >= (N-max (L~ (Cage (C,n)))) `1 by PSCOMP_1:71;
(N-max (L~ (Cage (C,n)))) `1 > (N-min (L~ (Cage (C,n)))) `1 by SPRECT_2:55;
hence contradiction by A50, A51, EUCLID:56; :: thesis: verum
end;
suppose x = W-min (L~ (Cage (C,n))) ; :: thesis: contradiction
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A13, A43, JORDAN1F:8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A42, PARTFUN1:def 8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) = p by A1, Th43;
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) = p by A42, PARTFUN1:def 8;
hence contradiction by A3, JORDAN1F:8; :: thesis: verum
end;
end;
end;
hence contradiction ; :: thesis: verum
end;
suppose A52: x in LSeg (((Rev RCutUS) /. (len (Rev RCutUS))),(SW-corner (L~ (Cage (C,n))))) ; :: thesis: contradiction
(W-min (L~ (Cage (C,n)))) `2 >= (SW-corner (L~ (Cage (C,n)))) `2 by PSCOMP_1:87;
then A53: (W-min (L~ (Cage (C,n)))) `2 >= x `2 by A31, A52, TOPREAL1:10;
A54: (W-min (L~ (Cage (C,n)))) `1 = W-bound (L~ (Cage (C,n))) by EUCLID:56;
(SW-corner (L~ (Cage (C,n)))) `1 = W-bound (L~ (Cage (C,n))) by EUCLID:56;
then A55: x `1 = W-bound (L~ (Cage (C,n))) by A31, A52, A54, GOBOARD7:5;
L~ (Cage (C,n)) = (L~ (Lower_Seq (C,n))) \/ (L~ (Upper_Seq (C,n))) by JORDAN1E:17;
then L~ (Lower_Seq (C,n)) c= L~ (Cage (C,n)) by XBOOLE_1:7;
then x in W-most (L~ (Cage (C,n))) by A47, A55, SPRECT_2:16;
then x `2 >= (W-min (L~ (Cage (C,n)))) `2 by PSCOMP_1:88;
then x `2 = (W-min (L~ (Cage (C,n)))) `2 by A53, XXREAL_0:1;
then x = W-min (L~ (Cage (C,n))) by A54, A55, TOPREAL3:11;
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A13, A43, JORDAN1F:8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A42, PARTFUN1:def 8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) = p by A1, Th43;
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) = p by A42, PARTFUN1:def 8;
hence contradiction by A3, JORDAN1F:8; :: thesis: verum
end;
end;
end;
hence contradiction ; :: thesis: verum
end;
suppose A56: W-min (L~ (Cage (C,n))) = SW-corner (L~ (Cage (C,n))) ; :: thesis: contradiction
set h = R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))));
A57: 2 <= len g by TOPREAL1:def 10;
W-max (L~ (Cage (C,n))) in L~ (Cage (C,n)) by SPRECT_1:15;
then A58: N-bound (L~ (Cage (C,n))) >= (W-max (L~ (Cage (C,n)))) `2 by PSCOMP_1:71;
A59: N-min (L~ (Cage (C,n))) in L~ (Upper_Seq (C,n)) by Th7;
then <*(N-min (L~ (Cage (C,n))))*> is_in_the_area_of Cage (C,n) by JORDAN1E:21, SPRECT_3:63;
then A60: R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) is_in_the_area_of Cage (C,n) by A59, JORDAN1E:21, SPRECT_3:69;
(W-max (L~ (Cage (C,n)))) `2 > (W-min (L~ (Cage (C,n)))) `2 by SPRECT_2:61;
then N-min (L~ (Cage (C,n))) <> (Upper_Seq (C,n)) . 1 by A12, A58, EUCLID:56;
then reconsider RCutUS = R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) as being_S-Seq FinSequence of (TOP-REAL 2) by A59, JORDAN3:70;
A61: len RCutUS >= 2 by TOPREAL1:def 10;
(R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) /. (len (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))))) = N-min (L~ (Cage (C,n))) by A59, Th45;
then A62: ((R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) /. (len (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))))) `2 = N-bound (L~ (Cage (C,n))) by EUCLID:56;
RCutUS /. 1 = (Upper_Seq (C,n)) /. 1 by A59, SPRECT_3:39
.= W-min (L~ (Cage (C,n))) by JORDAN1F:5 ;
then ((R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) /. 1) `2 = S-bound (L~ (Cage (C,n))) by A56, EUCLID:56;
then R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n))))) is_a_v.c._for Cage (C,n) by A60, A62, SPRECT_2:def 3;
then L~ g meets L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A10, A57, A61, SPRECT_2:33;
then consider x being set such that
A63: x in L~ g and
A64: x in L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by XBOOLE_0:3;
reconsider x = x as Point of (TOP-REAL 2) by A63;
A65: len (Lower_Seq (C,n)) in dom (Lower_Seq (C,n)) by FINSEQ_5:6;
A66: L~ g c= L~ (Lower_Seq (C,n)) by A1, A13, JORDAN3:76;
A67: len (Upper_Seq (C,n)) in dom (Upper_Seq (C,n)) by FINSEQ_5:6;
L~ RCutUS c= L~ (Upper_Seq (C,n)) by Th7, JORDAN3:76;
then x in (L~ (Lower_Seq (C,n))) /\ (L~ (Upper_Seq (C,n))) by A63, A64, A66, XBOOLE_0:def 4;
then A68: x in {(E-max (L~ (Cage (C,n)))),(W-min (L~ (Cage (C,n))))} by JORDAN1E:20;
now
per cases ( x = E-max (L~ (Cage (C,n))) or x = W-min (L~ (Cage (C,n))) ) by A68, TARSKI:def 2;
suppose x = E-max (L~ (Cage (C,n))) ; :: thesis: contradiction
then (Upper_Seq (C,n)) /. (len (Upper_Seq (C,n))) in L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A64, JORDAN1F:7;
then (Upper_Seq (C,n)) . (len (Upper_Seq (C,n))) in L~ (R_Cut ((Upper_Seq (C,n)),(N-min (L~ (Cage (C,n)))))) by A67, PARTFUN1:def 8;
then (Upper_Seq (C,n)) . (len (Upper_Seq (C,n))) = N-min (L~ (Cage (C,n))) by A59, Th43;
then (Upper_Seq (C,n)) /. (len (Upper_Seq (C,n))) = N-min (L~ (Cage (C,n))) by A67, PARTFUN1:def 8;
then A69: E-max (L~ (Cage (C,n))) = N-min (L~ (Cage (C,n))) by JORDAN1F:7;
N-max (L~ (Cage (C,n))) in L~ (Cage (C,n)) by SPRECT_1:13;
then A70: E-bound (L~ (Cage (C,n))) >= (N-max (L~ (Cage (C,n)))) `1 by PSCOMP_1:71;
(N-max (L~ (Cage (C,n)))) `1 > (N-min (L~ (Cage (C,n)))) `1 by SPRECT_2:55;
hence contradiction by A69, A70, EUCLID:56; :: thesis: verum
end;
suppose x = W-min (L~ (Cage (C,n))) ; :: thesis: contradiction
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A13, A63, JORDAN1F:8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) in L~ (R_Cut ((Lower_Seq (C,n)),p)) by A65, PARTFUN1:def 8;
then (Lower_Seq (C,n)) . (len (Lower_Seq (C,n))) = p by A1, Th43;
then (Lower_Seq (C,n)) /. (len (Lower_Seq (C,n))) = p by A65, PARTFUN1:def 8;
hence contradiction by A3, JORDAN1F:8; :: thesis: verum
end;
end;
end;
hence contradiction ; :: thesis: verum
end;
end;
end;
hence contradiction ; :: thesis: verum