let X be non empty set ; for S being SigmaField of X
for f being PartFunc of X,REAL
for A being Element of S
for r, s being Real st f is A -measurable & A c= dom f holds
(A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
let S be SigmaField of X; for f being PartFunc of X,REAL
for A being Element of S
for r, s being Real st f is A -measurable & A c= dom f holds
(A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
let f be PartFunc of X,REAL; for A being Element of S
for r, s being Real st f is A -measurable & A c= dom f holds
(A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
let A be Element of S; for r, s being Real st f is A -measurable & A c= dom f holds
(A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
let r, s be Real; ( f is A -measurable & A c= dom f implies (A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S )
assume that
A1:
f is A -measurable
and
A2:
A c= dom f
; (A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
R_EAL f is A -measurable
by A1;
then A3:
A /\ (less_dom ((R_EAL f),s)) in S
by MESFUNC1:def 16;
A4: (A /\ (great_eq_dom (f,r))) /\ (A /\ (less_dom (f,s))) =
((A /\ (great_eq_dom (f,r))) /\ A) /\ (less_dom (f,s))
by XBOOLE_1:16
.=
((great_eq_dom (f,r)) /\ (A /\ A)) /\ (less_dom (f,s))
by XBOOLE_1:16
;
A /\ (great_eq_dom (f,r)) in S
by A1, A2, Th13;
hence
(A /\ (great_eq_dom (f,r))) /\ (less_dom (f,s)) in S
by A3, A4, FINSUB_1:def 2; verum