let Omega be non empty set ; for Sigma being SigmaField of Omega
for P being Probability of Sigma
for A being Element of COM (Sigma,P)
for B being set st B in ProbPart A holds
P . B = (COM P) . A
let Sigma be SigmaField of Omega; for P being Probability of Sigma
for A being Element of COM (Sigma,P)
for B being set st B in ProbPart A holds
P . B = (COM P) . A
let P be Probability of Sigma; for A being Element of COM (Sigma,P)
for B being set st B in ProbPart A holds
P . B = (COM P) . A
let A be Element of COM (Sigma,P); for B being set st B in ProbPart A holds
P . B = (COM P) . A
let B be set ; ( B in ProbPart A implies P . B = (COM P) . A )
assume A1:
B in ProbPart A
; P . B = (COM P) . A
reconsider C = A \ B as thin of P by A1, Def7;
A2:
B in Sigma
by A1, Def7;
B c= A
by A1, Def7;
then A3:
A = B \/ C
by XBOOLE_1:45;
Sigma c= COM (Sigma,P)
by Th28;
then reconsider B = B as Event of COM (Sigma,P) by A2;
reconsider A = A as Event of COM (Sigma,P) ;
B misses C
by XBOOLE_1:79;
then A4: (COM P) . A =
((COM P) . B) + ((COM P) . C)
by A3, PROB_1:def 8
.=
((COM P) . B) + 0
by Th40
.=
(COM P) . B
;
reconsider B = B as Event of Sigma by A1, Def7;
(COM P) . A = P . B
by A4, Th39;
hence
P . B = (COM P) . A
; verum