:: On Rectangular Finite Sequences of the Points of the Plane
:: by Andrzej Trybulec and Yatsuka Nakamura
::
:: Received November 30, 1997
:: Copyright (c) 1997-2012 Association of Mizar Users


begin

registration
cluster non empty V19() V22( NAT ) Function-like constant V32() FinSequence-like FinSubsequence-like for set ;
existence
 ex b1 being FinSequence st
( not b1 is empty & b1 is constant )
proofend;
end;

theorem Th1: :: SPRECT_1:1
for f, g being FinSequence st f ^ g is constant holds
( f is constant & g is constant )
proofend;

theorem Th2: :: SPRECT_1:2
for x, y being set st <*x,y*> is constant holds
x = y
proofend;

theorem Th3: :: SPRECT_1:3
for x, y, z being set st <*x,y,z*> is constant holds
( x = y &amp; y = z &amp; z = x )
proofend;

begin

theorem Th4: :: SPRECT_1:4
for GX being non empty TopSpace
for A being Subset of GX
for B being non empty Subset of GX st A is_a_component_of B holds
A <> {}
proofend;

theorem Th5: :: SPRECT_1:5
for GX being TopStruct
for A, B being Subset of GX st A is_a_component_of B holds
A c= B
proofend;

theorem Th6: :: SPRECT_1:6
for T being non empty TopSpace
for A being non empty Subset of T
for B1, B2, S being Subset of T st B1 is_a_component_of A &amp; B2 is_a_component_of A &amp; S is_a_component_of A &amp; B1 \/ B2 = A &amp; not S = B1 holds
S = B2
proofend;

theorem Th7: :: SPRECT_1:7
for T being non empty TopSpace
for A being non empty Subset of T
for B1, B2, C1, C2 being Subset of T st B1 is_a_component_of A &amp; B2 is_a_component_of A &amp; C1 is_a_component_of A &amp; C2 is_a_component_of A &amp; B1 \/ B2 = A &amp; C1 \/ C2 = A holds
{B1,B2} = {C1,C2}
proofend;

begin

theorem Th8: :: SPRECT_1:8
for p, q, r being Point of (TOP-REAL 2) holds L~ <*p,q,r*> = (LSeg (p,q)) \/ (LSeg (q,r))
proofend;

registration
let n be Element of NAT ;
let f be non trivial FinSequence of (TOP-REAL n);
cluster L~ f ->  non empty ;
coherence
 not L~ f is empty
proofend;
end;

registration
let f be FinSequence of (TOP-REAL 2);
cluster L~ f ->  compact ;
coherence
 L~ f is compact
proofend;
end;

theorem Th9: :: SPRECT_1:9
for A, B being Subset of (TOP-REAL 2) st A c= B &amp; B is horizontal holds
A is horizontal
proofend;

theorem Th10: :: SPRECT_1:10
for A, B being Subset of (TOP-REAL 2) st A c= B &amp; B is vertical holds
A is vertical
proofend;

registration
cluster R^2-unit_square  ->  special_polygonal non horizontal non vertical ;
coherence
 ( R^2-unit_square is special_polygonal &amp; not R^2-unit_square is horizontal &amp; not R^2-unit_square is vertical )
proofend;
end;

registration
cluster non empty compact non horizontal non vertical for Element of bool the carrier of (TOP-REAL 2);
existence
 ex b1 being Subset of (TOP-REAL 2) st
( not b1 is vertical &amp; not b1 is horizontal &amp; not b1 is empty &amp; b1 is compact )
proofend;
end;

begin

theorem Th11: :: SPRECT_1:11
for C being non empty compact Subset of (TOP-REAL 2) holds
( N-min C in C &amp; N-max C in C )
proofend;

theorem Th12: :: SPRECT_1:12
for C being non empty compact Subset of (TOP-REAL 2) holds
( S-min C in C &amp; S-max C in C )
proofend;

theorem Th13: :: SPRECT_1:13
for C being non empty compact Subset of (TOP-REAL 2) holds
( W-min C in C &amp; W-max C in C )
proofend;

theorem Th14: :: SPRECT_1:14
for C being non empty compact Subset of (TOP-REAL 2) holds
( E-min C in C &amp; E-max C in C )
proofend;

theorem Th15: :: SPRECT_1:15
for C being non empty compact Subset of (TOP-REAL 2) holds
( C is vertical iff W-bound C = E-bound C )
proofend;

theorem Th16: :: SPRECT_1:16
for C being non empty compact Subset of (TOP-REAL 2) holds
( C is horizontal iff S-bound C = N-bound C )
proofend;

theorem :: SPRECT_1:17
for C being non empty compact Subset of (TOP-REAL 2) st NW-corner C = NE-corner C holds
C is vertical
proofend;

theorem :: SPRECT_1:18
for C being non empty compact Subset of (TOP-REAL 2) st SW-corner C = SE-corner C holds
C is vertical
proofend;

theorem :: SPRECT_1:19
for C being non empty compact Subset of (TOP-REAL 2) st NW-corner C = SW-corner C holds
C is horizontal
proofend;

theorem :: SPRECT_1:20
for C being non empty compact Subset of (TOP-REAL 2) st NE-corner C = SE-corner C holds
C is horizontal
proofend;

theorem Th21: :: SPRECT_1:21
for C being non empty compact Subset of (TOP-REAL 2) holds W-bound C <= E-bound C
proofend;

theorem Th22: :: SPRECT_1:22
for C being non empty compact Subset of (TOP-REAL 2) holds S-bound C <= N-bound C
proofend;

theorem Th23: :: SPRECT_1:23
for C being non empty compact Subset of (TOP-REAL 2) holds LSeg ((SE-corner C),(NE-corner C)) =  {  p where p is Point of (TOP-REAL 2) : ( p `1 = E-bound C &amp; p `2 <= N-bound C &amp; p `2 >= S-bound C )  }
proofend;

theorem Th24: :: SPRECT_1:24
for C being non empty compact Subset of (TOP-REAL 2) holds LSeg ((SW-corner C),(SE-corner C)) =  {  p where p is Point of (TOP-REAL 2) : ( p `1 <= E-bound C &amp; p `1 >= W-bound C &amp; p `2 = S-bound C )  }
proofend;

theorem Th25: :: SPRECT_1:25
for C being non empty compact Subset of (TOP-REAL 2) holds LSeg ((NW-corner C),(NE-corner C)) =  {  p where p is Point of (TOP-REAL 2) : ( p `1 <= E-bound C &amp; p `1 >= W-bound C &amp; p `2 = N-bound C )  }
proofend;

theorem Th26: :: SPRECT_1:26
for C being non empty compact Subset of (TOP-REAL 2) holds LSeg ((SW-corner C),(NW-corner C)) =  {  p where p is Point of (TOP-REAL 2) : ( p `1 = W-bound C &amp; p `2 <= N-bound C &amp; p `2 >= S-bound C )  }
proofend;

theorem :: SPRECT_1:27
for C being non empty compact Subset of (TOP-REAL 2) holds (LSeg ((SW-corner C),(NW-corner C))) /\ (LSeg ((NW-corner C),(NE-corner C))) = {(NW-corner C)}
proofend;

theorem Th28: :: SPRECT_1:28
for C being non empty compact Subset of (TOP-REAL 2) holds (LSeg ((NW-corner C),(NE-corner C))) /\ (LSeg ((NE-corner C),(SE-corner C))) = {(NE-corner C)}
proofend;

theorem Th29: :: SPRECT_1:29
for C being non empty compact Subset of (TOP-REAL 2) holds (LSeg ((SE-corner C),(NE-corner C))) /\ (LSeg ((SW-corner C),(SE-corner C))) = {(SE-corner C)}
proofend;

theorem Th30: :: SPRECT_1:30
for C being non empty compact Subset of (TOP-REAL 2) holds (LSeg ((NW-corner C),(SW-corner C))) /\ (LSeg ((SW-corner C),(SE-corner C))) = {(SW-corner C)}
proofend;

begin

theorem Th31: :: SPRECT_1:31
for D1 being non empty compact non vertical Subset of (TOP-REAL 2) holds W-bound D1 < E-bound D1
proofend;

theorem Th32: :: SPRECT_1:32
for D2 being non empty compact non horizontal Subset of (TOP-REAL 2) holds S-bound D2 < N-bound D2
proofend;

theorem Th33: :: SPRECT_1:33
for D1 being non empty compact non vertical Subset of (TOP-REAL 2) holds LSeg ((SW-corner D1),(NW-corner D1)) misses LSeg ((SE-corner D1),(NE-corner D1))
proofend;

theorem Th34: :: SPRECT_1:34
for D2 being non empty compact non horizontal Subset of (TOP-REAL 2) holds LSeg ((SW-corner D2),(SE-corner D2)) misses LSeg ((NW-corner D2),(NE-corner D2))
proofend;

begin

definition
let C be Subset of (TOP-REAL 2);
func SpStSeq C ->  FinSequence of (TOP-REAL 2) equals :: SPRECT_1:def 1
<*(NW-corner C),(NE-corner C),(SE-corner C)*> ^ <*(SW-corner C),(NW-corner C)*>;
coherence
 <*(NW-corner C),(NE-corner C),(SE-corner C)*> ^ <*(SW-corner C),(NW-corner C)*> is FinSequence of (TOP-REAL 2) ;
end;

:: deftheorem  defines SpStSeq SPRECT_1:def_1_:_
 for C being Subset of (TOP-REAL 2) holds SpStSeq C = <*(NW-corner C),(NE-corner C),(SE-corner C)*> ^ <*(SW-corner C),(NW-corner C)*>;

theorem Th35: :: SPRECT_1:35
for S being Subset of (TOP-REAL 2) holds (SpStSeq S) /. 1 = NW-corner S
proofend;

theorem Th36: :: SPRECT_1:36
for S being Subset of (TOP-REAL 2) holds (SpStSeq S) /. 2 = NE-corner S
proofend;

theorem Th37: :: SPRECT_1:37
for S being Subset of (TOP-REAL 2) holds (SpStSeq S) /. 3 = SE-corner S
proofend;

theorem Th38: :: SPRECT_1:38
for S being Subset of (TOP-REAL 2) holds (SpStSeq S) /. 4 = SW-corner S
proofend;

theorem :: SPRECT_1:39
for S being Subset of (TOP-REAL 2) holds (SpStSeq S) /. 5 = NW-corner S
proofend;

theorem Th40: :: SPRECT_1:40
for S being Subset of (TOP-REAL 2) holds len (SpStSeq S) = 5
proofend;

theorem Th41: :: SPRECT_1:41
for S being Subset of (TOP-REAL 2) holds L~ (SpStSeq S) = ((LSeg ((NW-corner S),(NE-corner S))) \/ (LSeg ((NE-corner S),(SE-corner S)))) \/ ((LSeg ((SE-corner S),(SW-corner S))) \/ (LSeg ((SW-corner S),(NW-corner S))))
proofend;

registration
let D be non empty compact non vertical Subset of (TOP-REAL 2);
cluster SpStSeq D ->  non constant ;
coherence
 not SpStSeq D is constant
proofend;
end;

registration
let D be non empty compact non horizontal Subset of (TOP-REAL 2);
cluster SpStSeq D ->  non constant ;
coherence
 not SpStSeq D is constant
proofend;
end;

registration
let D be non empty compact non horizontal non vertical Subset of (TOP-REAL 2);
cluster SpStSeq D ->  circular special unfolded s.c.c. standard ;
coherence
 ( SpStSeq D is special &amp; SpStSeq D is unfolded &amp; SpStSeq D is circular &amp; SpStSeq D is s.c.c. &amp; SpStSeq D is standard )
proofend;
end;

theorem Th42: :: SPRECT_1:42
for D being non empty compact non horizontal non vertical Subset of (TOP-REAL 2) holds L~ (SpStSeq D) = [.(W-bound D),(E-bound D),(S-bound D),(N-bound D).]
proofend;

registration
let T be non empty TopSpace;
let X be non empty compact Subset of T;
let f be continuous RealMap of T;
clusterf .: X ->  bounded_below ;
coherence
 f .: X is bounded_below
proofend;
clusterf .: X ->  bounded_above ;
coherence
 f .: X is bounded_above
proofend;
end;

theorem Th43: :: SPRECT_1:43
for S being Subset of (TOP-REAL 2) holds W-bound S = lower_bound (proj1 .: S)
proofend;

theorem Th44: :: SPRECT_1:44
for S being Subset of (TOP-REAL 2) holds S-bound S = lower_bound (proj2 .: S)
proofend;

theorem Th45: :: SPRECT_1:45
for S being Subset of (TOP-REAL 2) holds N-bound S = upper_bound (proj2 .: S)
proofend;

theorem Th46: :: SPRECT_1:46
for S being Subset of (TOP-REAL 2) holds E-bound S = upper_bound (proj1 .: S)
proofend;

theorem Th47: :: SPRECT_1:47
for S being Subset of (TOP-REAL 2)
for C1, C2 being non empty compact Subset of (TOP-REAL 2) st S = C1 \/ C2 holds
W-bound S = min ((W-bound C1),(W-bound C2))
proofend;

theorem Th48: :: SPRECT_1:48
for S being Subset of (TOP-REAL 2)
for C1, C2 being non empty compact Subset of (TOP-REAL 2) st S = C1 \/ C2 holds
S-bound S = min ((S-bound C1),(S-bound C2))
proofend;

theorem Th49: :: SPRECT_1:49
for S being Subset of (TOP-REAL 2)
for C1, C2 being non empty compact Subset of (TOP-REAL 2) st S = C1 \/ C2 holds
N-bound S = max ((N-bound C1),(N-bound C2))
proofend;

theorem Th50: :: SPRECT_1:50
for S being Subset of (TOP-REAL 2)
for C1, C2 being non empty compact Subset of (TOP-REAL 2) st S = C1 \/ C2 holds
E-bound S = max ((E-bound C1),(E-bound C2))
proofend;

registration
let r1, r2 be real number ;
clusterK76(r1,r2) ->  real-bounded for Subset of REAL;
coherence
 for b1 being Subset of REAL st b1 = [.r1,r2.] holds
b1 is real-bounded
proofend;
end;

theorem Th51: :: SPRECT_1:51
for r1, r2, t being Real st r1 <= r2 holds
( t in [.r1,r2.] iff ex s1 being Real st
( 0 <= s1 &amp; s1 <= 1 &amp; t = (s1 * r1) + ((1 - s1) * r2) ) )
proofend;

theorem Th52: :: SPRECT_1:52
for p, q being Point of (TOP-REAL 2) st p `1 <= q `1 holds
proj1 .: (LSeg (p,q)) = [.(p `1),(q `1).]
proofend;

theorem Th53: :: SPRECT_1:53
for p, q being Point of (TOP-REAL 2) st p `2 <= q `2 holds
proj2 .: (LSeg (p,q)) = [.(p `2),(q `2).]
proofend;

theorem Th54: :: SPRECT_1:54
for p, q being Point of (TOP-REAL 2) st p `1 <= q `1 holds
W-bound (LSeg (p,q)) = p `1
proofend;

theorem Th55: :: SPRECT_1:55
for p, q being Point of (TOP-REAL 2) st p `2 <= q `2 holds
S-bound (LSeg (p,q)) = p `2
proofend;

theorem Th56: :: SPRECT_1:56
for p, q being Point of (TOP-REAL 2) st p `2 <= q `2 holds
N-bound (LSeg (p,q)) = q `2
proofend;

theorem Th57: :: SPRECT_1:57
for p, q being Point of (TOP-REAL 2) st p `1 <= q `1 holds
E-bound (LSeg (p,q)) = q `1
proofend;

theorem Th58: :: SPRECT_1:58
for C being non empty compact Subset of (TOP-REAL 2) holds W-bound (L~ (SpStSeq C)) = W-bound C
proofend;

theorem Th59: :: SPRECT_1:59
for C being non empty compact Subset of (TOP-REAL 2) holds S-bound (L~ (SpStSeq C)) = S-bound C
proofend;

theorem Th60: :: SPRECT_1:60
for C being non empty compact Subset of (TOP-REAL 2) holds N-bound (L~ (SpStSeq C)) = N-bound C
proofend;

theorem Th61: :: SPRECT_1:61
for C being non empty compact Subset of (TOP-REAL 2) holds E-bound (L~ (SpStSeq C)) = E-bound C
proofend;

theorem Th62: :: SPRECT_1:62
for C being non empty compact Subset of (TOP-REAL 2) holds NW-corner (L~ (SpStSeq C)) = NW-corner C
proofend;

theorem Th63: :: SPRECT_1:63
for C being non empty compact Subset of (TOP-REAL 2) holds NE-corner (L~ (SpStSeq C)) = NE-corner C
proofend;

theorem Th64: :: SPRECT_1:64
for C being non empty compact Subset of (TOP-REAL 2) holds SW-corner (L~ (SpStSeq C)) = SW-corner C
proofend;

theorem Th65: :: SPRECT_1:65
for C being non empty compact Subset of (TOP-REAL 2) holds SE-corner (L~ (SpStSeq C)) = SE-corner C
proofend;

theorem Th66: :: SPRECT_1:66
for C being non empty compact Subset of (TOP-REAL 2) holds W-most (L~ (SpStSeq C)) = LSeg ((SW-corner C),(NW-corner C))
proofend;

theorem Th67: :: SPRECT_1:67
for C being non empty compact Subset of (TOP-REAL 2) holds N-most (L~ (SpStSeq C)) = LSeg ((NW-corner C),(NE-corner C))
proofend;

theorem Th68: :: SPRECT_1:68
for C being non empty compact Subset of (TOP-REAL 2) holds S-most (L~ (SpStSeq C)) = LSeg ((SW-corner C),(SE-corner C))
proofend;

theorem Th69: :: SPRECT_1:69
for C being non empty compact Subset of (TOP-REAL 2) holds E-most (L~ (SpStSeq C)) = LSeg ((SE-corner C),(NE-corner C))
proofend;

theorem Th70: :: SPRECT_1:70
for C being non empty compact Subset of (TOP-REAL 2) holds proj2 .: (LSeg ((SW-corner C),(NW-corner C))) = [.(S-bound C),(N-bound C).]
proofend;

theorem Th71: :: SPRECT_1:71
for C being non empty compact Subset of (TOP-REAL 2) holds proj1 .: (LSeg ((NW-corner C),(NE-corner C))) = [.(W-bound C),(E-bound C).]
proofend;

theorem Th72: :: SPRECT_1:72
for C being non empty compact Subset of (TOP-REAL 2) holds proj2 .: (LSeg ((NE-corner C),(SE-corner C))) = [.(S-bound C),(N-bound C).]
proofend;

theorem Th73: :: SPRECT_1:73
for C being non empty compact Subset of (TOP-REAL 2) holds proj1 .: (LSeg ((SE-corner C),(SW-corner C))) = [.(W-bound C),(E-bound C).]
proofend;

theorem Th74: :: SPRECT_1:74
for C being non empty compact Subset of (TOP-REAL 2) holds W-min (L~ (SpStSeq C)) = SW-corner C
proofend;

theorem Th75: :: SPRECT_1:75
for C being non empty compact Subset of (TOP-REAL 2) holds W-max (L~ (SpStSeq C)) = NW-corner C
proofend;

theorem Th76: :: SPRECT_1:76
for C being non empty compact Subset of (TOP-REAL 2) holds N-min (L~ (SpStSeq C)) = NW-corner C
proofend;

theorem Th77: :: SPRECT_1:77
for C being non empty compact Subset of (TOP-REAL 2) holds N-max (L~ (SpStSeq C)) = NE-corner C
proofend;

theorem Th78: :: SPRECT_1:78
for C being non empty compact Subset of (TOP-REAL 2) holds E-min (L~ (SpStSeq C)) = SE-corner C
proofend;

theorem Th79: :: SPRECT_1:79
for C being non empty compact Subset of (TOP-REAL 2) holds E-max (L~ (SpStSeq C)) = NE-corner C
proofend;

theorem Th80: :: SPRECT_1:80
for C being non empty compact Subset of (TOP-REAL 2) holds S-min (L~ (SpStSeq C)) = SW-corner C
proofend;

theorem Th81: :: SPRECT_1:81
for C being non empty compact Subset of (TOP-REAL 2) holds S-max (L~ (SpStSeq C)) = SE-corner C
proofend;

begin

definition
let f be FinSequence of (TOP-REAL 2);
attrf is rectangular  means :Def2: :: SPRECT_1:def 2
 ex D being non empty compact non horizontal non vertical Subset of (TOP-REAL 2) st f = SpStSeq D;
end;

:: deftheorem Def2 defines rectangular SPRECT_1:def_2_:_
 for f being FinSequence of (TOP-REAL 2) holds
( f is rectangular iff ex D being non empty compact non horizontal non vertical Subset of (TOP-REAL 2) st f = SpStSeq D );

registration
let D be non empty compact non horizontal non vertical Subset of (TOP-REAL 2);
cluster SpStSeq D ->  rectangular ;
coherence
 SpStSeq D is rectangular by Def2;
end;

registration
clusterV19() V22( NAT ) V23( the carrier of (TOP-REAL 2)) Function-like V32() FinSequence-like FinSubsequence-like rectangular for FinSequence of the carrier of (TOP-REAL 2);
existence
 ex b1 being FinSequence of (TOP-REAL 2) st b1 is rectangular
proofend;
end;

theorem :: SPRECT_1:82
for s being rectangular FinSequence of (TOP-REAL 2) holds len s = 5
proofend;

registration
cluster rectangular  ->  non constant for FinSequence of the carrier of (TOP-REAL 2);
coherence
 for b1 being FinSequence of (TOP-REAL 2) st b1 is rectangular holds
not b1 is constant
proofend;
end;

registration
cluster non empty rectangular  ->  non empty circular special unfolded s.c.c. standard for FinSequence of the carrier of (TOP-REAL 2);
coherence
 for b1 being non empty FinSequence of (TOP-REAL 2) st b1 is rectangular holds
( b1 is standard &amp; b1 is special &amp; b1 is unfolded &amp; b1 is circular &amp; b1 is s.c.c. )
proofend;
end;

:: Special points of L~f, f - rectangular
theorem :: SPRECT_1:83
for s being rectangular FinSequence of (TOP-REAL 2) holds
( s /. 1 = N-min (L~ s) &amp; s /. 1 = W-max (L~ s) )
proofend;

theorem :: SPRECT_1:84
for s being rectangular FinSequence of (TOP-REAL 2) holds
( s /. 2 = N-max (L~ s) &amp; s /. 2 = E-max (L~ s) )
proofend;

theorem :: SPRECT_1:85
for s being rectangular FinSequence of (TOP-REAL 2) holds
( s /. 3 = S-max (L~ s) &amp; s /. 3 = E-min (L~ s) )
proofend;

theorem :: SPRECT_1:86
for s being rectangular FinSequence of (TOP-REAL 2) holds
( s /. 4 = S-min (L~ s) &amp; s /. 4 = W-min (L~ s) )
proofend;

begin

theorem Th87: :: SPRECT_1:87
for r1, r2, s1, s2 being Real st r1 < r2 &amp; s1 < s2 holds
[.r1,r2,s1,s2.] is Jordan
proofend;

registration
let f be rectangular FinSequence of (TOP-REAL 2);
cluster L~ f ->  Jordan ;
coherence
 L~ f is Jordan
proofend;
end;

definition
let S be Subset of (TOP-REAL 2);
redefine attr S is Jordan  means :Def3: :: SPRECT_1:def 3
( S ` <> {} &amp; ex A1, A2 being Subset of (TOP-REAL 2) st
( S ` = A1 \/ A2 &amp; A1 misses A2 &amp; (Cl A1) \ A1 = (Cl A2) \ A2 &amp; A1 is_a_component_of S ` &amp; A2 is_a_component_of S ` ) );
compatibility
 ( S is Jordan iff ( S ` <> {} &amp; ex A1, A2 being Subset of (TOP-REAL 2) st
( S ` = A1 \/ A2 &amp; A1 misses A2 &amp; (Cl A1) \ A1 = (Cl A2) \ A2 &amp; A1 is_a_component_of S ` &amp; A2 is_a_component_of S ` ) ) )
proofend;
end;

:: deftheorem Def3 defines Jordan SPRECT_1:def_3_:_
 for S being Subset of (TOP-REAL 2) holds
( S is Jordan iff ( S ` <> {} &amp; ex A1, A2 being Subset of (TOP-REAL 2) st
( S ` = A1 \/ A2 &amp; A1 misses A2 &amp; (Cl A1) \ A1 = (Cl A2) \ A2 &amp; A1 is_a_component_of S ` &amp; A2 is_a_component_of S ` ) ) );

theorem Th88: :: SPRECT_1:88
for f being rectangular FinSequence of (TOP-REAL 2) holds LeftComp f misses RightComp f
proofend;

registration
let f be non constant standard special_circular_sequence;
cluster LeftComp f ->  non empty ;
coherence
 not LeftComp f is empty
proofend;
cluster RightComp f ->  non empty ;
coherence
 not RightComp f is empty
proofend;
end;

theorem :: SPRECT_1:89
for f being rectangular FinSequence of (TOP-REAL 2) holds LeftComp f <> RightComp f
proofend;