let Omega be non empty set ; for Sigma being SigmaField of Omega
for P being Probability of Sigma
for A, B, C being Event of Sigma st A,B,C are_independent_respect_to P holds
A,C,B are_independent_respect_to P
let Sigma be SigmaField of Omega; for P being Probability of Sigma
for A, B, C being Event of Sigma st A,B,C are_independent_respect_to P holds
A,C,B are_independent_respect_to P
let P be Probability of Sigma; for A, B, C being Event of Sigma st A,B,C are_independent_respect_to P holds
A,C,B are_independent_respect_to P
let A, B, C be Event of Sigma; ( A,B,C are_independent_respect_to P implies A,C,B are_independent_respect_to P )
assume A1:
A,B,C are_independent_respect_to P
; A,C,B are_independent_respect_to P
then
P . ((A /\ B) /\ C) = ((P . A) * (P . B)) * (P . C)
by Th32;
then A2:
P . ((A /\ C) /\ B) = ((P . A) * (P . C)) * (P . B)
by XBOOLE_1:16;
B,C are_independent_respect_to P
by A1, Th32;
then A3:
C,B are_independent_respect_to P
by Th31;
( A,B are_independent_respect_to P & A,C are_independent_respect_to P )
by A1, Th32;
hence
A,C,B are_independent_respect_to P
by A2, A3, Th32; verum