let R be finite Approximation_Space; for X, Y, Z being Subset of R st X <> {} & Y <> {} & Z <> {} holds
((CMap (kappa_1 R)) . (X,Y)) + ((CMap (kappa_1 R)) . (Y,Z)) >= (CMap (kappa_1 R)) . (X,Z)
let X, Y, Z be Subset of R; ( X <> {} & Y <> {} & Z <> {} implies ((CMap (kappa_1 R)) . (X,Y)) + ((CMap (kappa_1 R)) . (Y,Z)) >= (CMap (kappa_1 R)) . (X,Z) )
assume ZZ:
( X <> {} & Y <> {} & Z <> {} )
; ((CMap (kappa_1 R)) . (X,Y)) + ((CMap (kappa_1 R)) . (Y,Z)) >= (CMap (kappa_1 R)) . (X,Z)
set m = card ((X \/ Y) \/ Z);
set m0 = card (X \ (Y \/ Z));
set m1 = card (Y \ (X \/ Z));
set m2 = card ((X /\ Y) \ Z);
set m3 = card ((X /\ Z) \ Y);
set m4 = card (Z \ (X \/ Y));
D1:
X \ (Y \/ Z) = (X \ Y) /\ (X \ Z)
by XBOOLE_1:53;
X /\ Z misses X \ Z
by XBOOLE_1:89;
then
(X /\ Z) \ Y misses X \ Z
by XBOOLE_1:80;
then D3b:
(card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y)) = card ((X \ (Y \/ Z)) \/ ((X /\ Z) \ Y))
by CARD_2:40, D1, XBOOLE_1:74;
Y =
(Y \ Z) \/ Y
by XBOOLE_1:12, XBOOLE_1:36
.=
((Y \/ Z) \ Z) \/ Y
by XBOOLE_1:40
.=
((Y \/ Z) \ Z) \/ ((Y \/ Z) /\ Y)
by XBOOLE_1:21
.=
(Y \/ Z) \ (Z \ Y)
by XBOOLE_1:52
;
then u1:
(X \ (Y \/ Z)) \/ (X /\ (Z \ Y)) = X \ Y
by XBOOLE_1:52;
X \ (Y \/ Z) misses X /\ Y
by D1, XBOOLE_1:74, XBOOLE_1:89;
then D2:
X \ (Y \/ Z) misses (X /\ Y) \ Z
by XBOOLE_1:63, XBOOLE_1:36;
D3:
(card (X \ (Y \/ Z))) + (card ((X /\ Y) \ Z)) = card ((X \ (Y \/ Z)) \/ ((X /\ Y) \ Z))
by D2, CARD_2:40;
Z =
(Z \ Y) \/ Z
by XBOOLE_1:12, XBOOLE_1:36
.=
((Y \/ Z) \ Y) \/ Z
by XBOOLE_1:40
.=
((Y \/ Z) \ Y) \/ ((Y \/ Z) /\ Z)
by XBOOLE_1:21
.=
(Y \/ Z) \ (Y \ Z)
by XBOOLE_1:52
;
then
(X \ (Y \/ Z)) \/ (X /\ (Y \ Z)) = X \ Z
by XBOOLE_1:52;
then Z2:
card (X \ Z) = (card (X \ (Y \/ Z))) + (card ((X /\ Y) \ Z))
by D3, XBOOLE_1:49;
d1:
Y \ (X \/ Z) c= Y \ X
by XBOOLE_1:34, XBOOLE_1:7;
X /\ Y misses Y \ X
by XBOOLE_1:89;
then
Y \ (X \/ Z) misses X /\ Y
by d1, XBOOLE_1:63;
then D2:
Y \ (X \/ Z) misses (X /\ Y) \ Z
by XBOOLE_1:63, XBOOLE_1:36;
D3a:
(card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z)) = card ((Y \ (X \/ Z)) \/ ((X /\ Y) \ Z))
by D2, CARD_2:40;
Z =
(Z \ X) \/ Z
by XBOOLE_1:12, XBOOLE_1:36
.=
((X \/ Z) \ X) \/ Z
by XBOOLE_1:40
.=
((X \/ Z) \ X) \/ ((X \/ Z) /\ Z)
by XBOOLE_1:21
.=
(X \/ Z) \ (X \ Z)
by XBOOLE_1:52
;
then aa:
(Y \ (X \/ Z)) \/ (Y /\ (X \ Z)) = Y \ Z
by XBOOLE_1:52;
then Z3:
card (Y \ Z) = (card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))
by D3a, XBOOLE_1:49;
(Z \ (X \/ Y)) \/ (X \/ Y) = (X \/ Y) \/ Z
by XBOOLE_1:39;
then x4:
(card (Z \ (X \/ Y))) + (card (X \/ Y)) = card ((X \/ Y) \/ Z)
by XBOOLE_1:79, CARD_2:40;
(Y \ (X \/ Z)) \/ (X \/ Z) =
Y \/ (X \/ Z)
by XBOOLE_1:39
.=
(X \/ Y) \/ Z
by XBOOLE_1:4
;
then z5:
(card (Y \ (X \/ Z))) + (card (X \/ Z)) = card ((X \/ Y) \/ Z)
by XBOOLE_1:79, CARD_2:40;
then
card (X \/ Z) = (card ((X \/ Y) \/ Z)) - (card (Y \ (X \/ Z)))
;
then U3:
card ((X \/ Y) \/ Z) > 0 + (card (Y \ (X \/ Z)))
by XREAL_1:20, ZZ;
(X \ (Y \/ Z)) \/ (Y \/ Z) =
X \/ (Y \/ Z)
by XBOOLE_1:39
.=
(X \/ Y) \/ Z
by XBOOLE_1:4
;
then Z6:
(card (X \ (Y \/ Z))) + (card (Y \/ Z)) = card ((X \/ Y) \/ Z)
by XBOOLE_1:79, CARD_2:40;
T1: (CMap (kappa_1 R)) . (X,Y) =
(card (X \ Y)) / (card (X \/ Y))
by ZZ, PropEx3
.=
((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / ((card ((X \/ Y) \/ Z)) - (card (Z \ (X \/ Y))))
by u1, x4, XBOOLE_1:49, D3b
;
T2: (CMap (kappa_1 R)) . (Y,Z) =
(card (Y \ Z)) / (card (Y \/ Z))
by ZZ, PropEx3
.=
((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / ((card ((X \/ Y) \/ Z)) - (card (X \ (Y \/ Z))))
by aa, Z6, XBOOLE_1:49, D3a
;
T3:
(CMap (kappa_1 R)) . (X,Z) = ((card (X \ (Y \/ Z))) + (card ((X /\ Y) \ Z))) / ((card ((X \/ Y) \/ Z)) - (card (Y \ (X \/ Z))))
by Z2, z5, ZZ, PropEx3;
0 <= card (Z \ (X \/ Y))
;
then
(card ((X \/ Y) \/ Z)) - (card ((X \/ Y) \/ Z)) <= card (Z \ (X \/ Y))
;
then
(card ((X \/ Y) \/ Z)) - (card (Z \ (X \/ Y))) <= card ((X \/ Y) \/ Z)
by XREAL_1:12;
then V1:
((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / ((card ((X \/ Y) \/ Z)) - (card (Z \ (X \/ Y)))) >= ((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / (card ((X \/ Y) \/ Z))
by XREAL_1:118, x4, ZZ;
0 <= card (X \ (Y \/ Z))
;
then
(card ((X \/ Y) \/ Z)) - (card ((X \/ Y) \/ Z)) <= card (X \ (Y \/ Z))
;
then
(card ((X \/ Y) \/ Z)) - (card (X \ (Y \/ Z))) <= card ((X \/ Y) \/ Z)
by XREAL_1:12;
then V2:
((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / ((card ((X \/ Y) \/ Z)) - (card (X \ (Y \/ Z)))) >= ((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z))
by XREAL_1:118, Z6, ZZ;
(card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y)) >= (card (X \ (Y \/ Z))) + 0
by XREAL_1:6;
then V3:
((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) + ((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) >= ((card (X \ (Y \/ Z))) + 0) + ((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z)))
by XREAL_1:6;
B2:
(((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / ((card ((X \/ Y) \/ Z)) - (card (Z \ (X \/ Y))))) + (((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / ((card ((X \/ Y) \/ Z)) - (card (X \ (Y \/ Z))))) >= (((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / (card ((X \/ Y) \/ Z))) + (((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z)))
by V1, V2, XREAL_1:7;
(((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / (card ((X \/ Y) \/ Z))) + (((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z))) = (((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) + ((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z)))) / (card ((X \/ Y) \/ Z))
by XCMPLX_1:62;
then B3:
(((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / (card ((X \/ Y) \/ Z))) + (((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z))) >= (((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z))
by V3, XREAL_1:72;
set a = ((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z));
set b = card ((X \/ Y) \/ Z);
F2:
((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z)) = (card (X \ (Y \/ Z))) + (card (Y \ Z))
by Z3;
X \ Y misses Y
by XBOOLE_1:79;
then
X \ Y misses Y \ Z
by XBOOLE_1:63, XBOOLE_1:36;
then
(X \ Y) /\ (X \ Z) misses Y \ Z
by XBOOLE_1:74;
then F5:
X \ (Y \/ Z) misses Y \ Z
by XBOOLE_1:53;
( X \ (Y \/ Z) c= X & Y \ Z c= Y )
by XBOOLE_1:36;
then F4:
(X \ (Y \/ Z)) \/ (Y \ Z) c= X \/ Y
by XBOOLE_1:13;
X \/ Y c= (X \/ Y) \/ Z
by XBOOLE_1:7;
then f6:
(X \ (Y \/ Z)) \/ (Y \ Z) c= (X \/ Y) \/ Z
by F4;
card ((X \ (Y \/ Z)) \/ (Y \ Z)) = ((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z))
by F2, F5, CARD_2:40;
then
(((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z)) >= ((((card (X \ (Y \/ Z))) + (card (Y \ (X \/ Z)))) + (card ((X /\ Y) \ Z))) - (card (Y \ (X \/ Z)))) / ((card ((X \/ Y) \/ Z)) - (card (Y \ (X \/ Z))))
by f6, U3, LemacikX, NAT_1:43;
then
(((card (X \ (Y \/ Z))) + (card ((X /\ Z) \ Y))) / (card ((X \/ Y) \/ Z))) + (((card (Y \ (X \/ Z))) + (card ((X /\ Y) \ Z))) / (card ((X \/ Y) \/ Z))) >= ((card (X \ (Y \/ Z))) + (card ((X /\ Y) \ Z))) / ((card ((X \/ Y) \/ Z)) - (card (Y \ (X \/ Z))))
by B3, XXREAL_0:2;
hence
((CMap (kappa_1 R)) . (X,Y)) + ((CMap (kappa_1 R)) . (Y,Z)) >= (CMap (kappa_1 R)) . (X,Z)
by T1, T2, T3, B2, XXREAL_0:2; verum